Editable_If

[Ahmad_1]

There is a common table
1- The first employee enters the data only
2- The other employee only inserts and updates some columns
It is required to prevent employee No. 2 from modifying some columns specified by the manager

[jyothis_m · Accepted solution]

User Settings: The Essentials

[jyothis_m]

You can try the following expression in editable-if

USEREMAIL() <> "employee2email"

for those columns which you want to prevent employee2. User signin required for this to work. 

[Ahmad_1]

But the username is used by both parties

[jyothis_m · Accepted solution]

User Settings: The Essentials

[Steve · Accepted solution]

Limit users to their own data - AppSheet Help

Limit users to particular tables, views, and actions - AppSheet Help