I need to create a sheet where one person can edit only what they typed.
Enrollment of people for individual classes, without the possibility of removing the previous person, i.e. if someone enters a given cell, it is only me (as administratpor) and this person can delete it, another student cannot delete the entry - can only fill in empty cells in order to enroll.
Hi, I hope I can help you. First of all, I have to answer your question with "No". As far as I know, there is no such possibility in Excel.
However, you can do something similar that might help you.
In a protected worksheet you can protect individual areas or a group of cells as an area with a separate password. If you know in advance in which cells your individual users of the worksheet are allowed to make their changes, you can provide the different areas with a separate password, which you then only give to the corresponding user. The users have to enter the password once before they can change "their" cells. If another user opens the sheet, he cannot change the entries of the other user.
If you are interested in this, take a look at the sheet protection options in Excel.