Is there a way to set a field with [Today] date and not have it change once it is set.
I have answered this question in another thread.
In general, you have to check if this field is empty before setting a value to it.
However, it is impossiple to check if a Date field is empty and you have to set value of your Date field to a String variable and then you can check if this String variable is empty.
Hope this approach could be used in your case. If so, please, don't forget to upvote and mark as answer :-).
You can update the field of a List Item in Workflow by using Update List Item action and setting the date column to Current Date
However permissions on columns are not permissible in SharePoint, what you can do is Hide this date column from the List/Library Forms by going into
This will hide the column from been updated by forms...
You can create a date field in your list and assign it a workflow that will run at item create or change, and check field is empty with if statement then set it with workflow comment 'Update List Item'. You can give it the Today value.