How do I make a number box contain one non-editable field and the other editable?

[sdhruv]

so I need to make a number label which looks like

MTF No. : xxx- 1223345

So MTF No. is the control source from the table, I need xxx to be added by me and remain unchanged while the user can input the second number box the number they want to(1223345).

[jonh]

Set an input mask?


"MTF No".\ :" xxx- "#######

[sdhruv]

Thanks a lot.