Field type ChangeUser as the ChangeTimestamp field

[albert_rev]

Just as I can store the date and time when an update is made in the registry, I would also like to store the username or usermail who made the updated.

[Suvrutt_Gurjar]

In general, if the user is updating the record through a form,  you can have a column such as [Updated_By] with an app formula as USEREMAIL()

[TeeSee1 · Accepted solution]

https://support.google.com/appsheet/answer/10106509?hl=en

Initial value and Reset on Edit can be used.