To prevent illegal working, employers must check that all prospective employees have the right to work in the UK before they start employment. Your business can be fined £20,000 for each person you employ who does not have the right to work in the UK. You are excused from paying if you can show that you made sufficient checks.
Covid-19 made it difficult for employers to safely carry out checks in person. So, on 30th March 2020, measures were introduced to temporarily allow employers to do these checks remotely. These measures end on 16th May 2021 meaning that you must revert to conducting full right to work checks from 17th May 2021.
What should you do?
There are three steps:
Obtain the employee's original documents as prescribed in the Home Office guidance.
Check (in the presence of the prospective employee) that the documents relate to that person and are original, unaltered, and valid.
Copy the documents, record the date you checked, the date for follow-up checks and retain hard or scanned copies.
Here (https://www.gov.uk/government/publications/right-to-work-checks-employers-guide) is the Home Office's guide on how and why to check, and the documents you can use.