I have an excel sheet that I update and want others to view it only(view
permissions only).

My Question is:

Can myself and other person edit the sheet at the same time?

Can I assign certain certain rows, columns only that someone can
edit(insert, update data)?

Can I make certain fields(columns/rows) mandatory while editing.
For eg, If I have a sheet with columns Name, City, St, Address, Zip
Can I make data in Zip column mandatory? (it has to be
populated)?

Thanks in Advance