If you are self-employed, you will likely be familiar with the process of submitting a Self Assessment tax return. This is an annual process that lets HMRC know how much you have earned in each tax year and other financial information so that HMRC can use the information to calculate the amount of tax and National Insurance contributions you need to pay.

Your tax return can be filed online via the HMRC website. You will need your Government Gateway account username and password to access the Self Assessment form. However, this can pose an issue if you have lost your user ID or password because you will be locked out of your online account.

Luckily, you don't need to contact HMRC directly if you are experiencing issues with a lost user ID or password. It's possible to find or reset the login details for your online account by following a few simple steps.

Continue reading to find out how you can register for the HMRC digital services and what to do if you forget your login information or experience other issues with your account.

Before you panic about losing your Self Assessment login details, it's a good idea to take a look at your email inbox to see if you have any records of your Government Gateway ID or password. You could try typing in 'Government Gateway user ID' into the search bar to see if any emails are brought up.

If you can't find any emails that contain your login information, you can go to the government website to recover your information. They will ask you to type in the email address that is associated with your account. You will then be asked to check your email inbox for a code that you will need to input on the government website. The code will expire after 30 minutes. After you have entered the code, you will be taken to another page that will ask you to type in the password to your account.

Once you have typed in your account password, you will be sent a text to the mobile number associated with your account. After you have successfully typed this in on the government webpage, your user ID will be displayed on the page and sent to your email address. You can then use the username and your password to log into your account.

You can go to the Government Gateway website and click the 'reset your password' option if you have forgotten your account's password. The website will then prompt you to type in the email address that is associated with your account so that they can send you a code (which will expire after 30 minutes). You will be asked to type this code in the relevant bar on the webpage.

The webpage will then instruct you to type in your Government Gateway ID. You will then be sent a code via a text message to the mobile phone number that you have previously linked with your Government Gateway account. After you have successfully entered the code onto the webpage, you will be prompted to create a new password.

The new password must contain 10 or more characters. HMRC recommends that you select three random words and put them together to create your Government Gateway password. It's also advised that your password features a mixture of letters, numbers and symbols to make the password stronger and more difficult for other people to guess.

It's advisable to make a unique password for your Self Assessment account that you don't already use for other online accounts. This protects your account because it means another individual won't be able to access it if they work out your master password from another online account.

You should avoid simple passwords such as 'password' and '12345' as these are easy to guess and would mean that other people could easily access your account. Your password should also be kept private so that no one else can access your account without your permission or knowledge. It's also advisable to refrain from writing the password down so that no one else can find it.

After enrolling for the online services, you will be sent a 12-digit activation code within 10 days if you are in the UK or 21 days if you are abroad. You won't be given a code if you are enrolling for a personal tax account. If you lose the code within 28 days of enrolling, you can sign into the HMRC online services and request a new code.

Your new code should arrive within the same period as your first code was sent (10 days or 21 days, respectively). Try to activate your account with the code as quickly as possible so that you don't have to request a new one.

You will be automatically locked out of your Government Gateway account if you enter the wrong username or password five times in a row. This is to protect your account in case someone else is trying to guess your login details. You will need to wait two hours before your account will automatically unlock, and you can try to log into it again. Unfortunately, the helpdesk cannot unlock your account on your behalf.

Sometimes the HMRC website will experience availability issues or will be down during scheduled maintenance. You can consult the HMRC service availability and issues page if you are experiencing issues logging into your account.

His Majesty's Revenue and Customs (HMRC) uses its online hub to offer various services. One of the features is Self Assessment online, which allows self-employed workers to complete and file their tax returns. You can also file a tax return using these services if you are not self-employed but need to complete a Self Assessment for another reason, such as showing evidence of your income from property rental.

You can use the online services to view previous tax returns that you have made, check that your personal and financial details are correct and print a copy of your tax calculation. You cannot, however, use the online services to file a return as part of your partnership, trust or estate, or if you live abroad as a non-resident.

The Self Assessment doesn't have to be completed in one sitting. You can save your progress and return to it at a later time if necessary.

You will need access to the following documents or information to complete your online tax return:

  • P60 or P45 if you have been employed within the relevant tax year
  • Evidence of other forms of income, including rental income
  • Records of work-related expenses, pension, student loan expenses etc
  • Benefit records

It's important that you have kept detailed records of your inbound and outgoing finances so that you can provide evidence to HMRC when required. You can also print the tax return off and post it to HMRC if you would prefer, although it's important that you don't accidentally leave any boxes blank.

If this is your first time filling out a Self Assessment, you will need to register for the HMRC online tax service. At the same time, you will need to register for Class 2 National Insurance. You can register for both through your business tax account, which you can log into using your Government Gateway user ID and password. If you don't have an HMRC login user ID, you can create one on the HMRC website.

After registering for a Government Gateway account or the Self Assessment online services, you will be sent a Unique Taxpayer Reference (UTR) number through the post within 10 days (or 21 days if you are based abroad). You will need to use your UTR to file a tax return.

HMRC will also send you a letter or email to remind you to complete your Self Assessment before the due date. You can file the return at any point before the deadline.

You need to file an annual Self Assessment tax return on a yearly basis if you are self-employed or need to show evidence of your income (such as rent). This can be completed online through the HMRC online services. To access this form, you will need your Government Gateway account username and password.

In the instance that you forget your login information for the online tax service, you can request a reminder for your username or create a new password. You will be sent a code to the email address that you submitted when you filled out your personal details to set up your account. After this, you will be sent another code to your mobile phone, which you will also have to fill out on the HMRC webpage.