Non repeated cell

how can i make the cell cannot accept repeated number , for example invoice number in the attached photo.

Manager is generally designed to allow a user to enter or partly enter anything the want but then flag erroneous entries. As such preventing entry of data into a user entry field is probably less likely to occur, instead this idea may achieve what you want

that mean “this case not solved yet” ?

That is correct. Suggestions are put into the ideas category to generate discussion. The developer might decide to implement them, or might not. To date, he has always chosen to give users more flexibility, not less. So there is nothing anywhere in the program at this time that prevents you from duplicating content in fields.

ok , thx friend about your co-operation