Using a text field to filter a Record Picker field

There is an option to turn that reference field into a search field when those lists get big.

Access the field properties for the "Related Category" and check the box to "use the record picker instead of a drop down menu"

Then a pop-up shows up for them to search by any of the key fields used in the record picker (you get up to 3 options)

The drop-down option will cease to function when your source-table has more than 1,000 records; so you would need to set your Record Picker to display the fields (there are 3 placeholders) in the order that makes sense for users typing-ahead their options.  It doesn't "show all options" that "contain" the user entry; it follows alphabetically the numbers/text they enter.

However; once your data source gets to 1,000 records; QuickBase will automatically move to the Record Picker Option instead of the drop down.

If the 3 fields in the placeholders are not flexible enough, build one or more formula fields; and then use those formula fields (which can string together more than 1 field of data) in the placeholders so that you get the equivalent of 4 or more fields of data available to view when selecting.

In a Form Layout you can also choose a custom report instead of a record picker for your reference field picker - this is especially useful if you want to use filters to exclude data from the record picker in addition to controlling how many, and the order of fields that appear in the record picker dialog window.

Thank you for very helpful suggestions.  What I really want is that "pop-up search text box" to be on the form itself. So the user can paste in a string and filter down to 1 or few items in the record picker.

In Native Quickbase, there are two methods to chose a parent method from a list.  It can be a drop down list if there are less than 1,000 choices or it can be forced to be the record picker pop up box in that separate window.

If you want it to work the way you are suggesting, then that would be a non native solution that someone would have to write as custom code to change the behaviour of the form.