Purchasing wants a form that users can use to order items related to COVID. The Description and Unit of Measure are determined. Users would select the quantity. I thought a table would be easiest but I'm not sure how to set it up where only one column is fillable. What would be best way to set this up?
Table in Forms
Adding to what Bert said, you can set individual columns to be read-only so they can only have values from the lookup. To do that, you can edit the table, then click Field Options check the read-only box.
A lookup rule is by far the best option, but as an alternative, you could also use calculations as long as the maximum number of rows is limited to how many items are listed in the calculation otherwise you would get an error because the row index would be out of range.
=INDEX(["Item 1","Item 2","Item 3"],ROW())
Would yield the following