I would like to set a password for a user and allow them to modify only selected fields in a layout. They would be able to see the other fields but only modify their specific fields. I cannot lock the other fields because others will log in and need to modify them. Do I have to create unique layouts for each user? I hope this is clear.

There are 2 ways to accomplish this.

One way is to create seperate layouts for each type of user or each access level. Where you would then lock or disallow access to fields as necessary.

The other method is to use the Access Privledges built into the Filemaker password system to make some fields read/only or hidden based upon the password entered when the files were opened.