It's been nearly five years since I've done anything in Access, so needless to say, I'm a bit rusty. I might even be using some terms incorrectly but I'll do the best I can.

What I'm attempting to do is set up a few different fields that use lookup tables to help populate the fields. I'm running in to a problem when I want to allow the user to enter information that isn't in the lookup tables. For instance, I'm currently working on a database that stores information about customers and their vehicles. In my Vehicle table I have a field labeled Fuel Type that links to a table that currently has two options, Gasoline and Diesel. If at some point in the future I want the user to be able to enter 'Hydrogen' into the Fuel Type field and have it stored in the Fuels table, how do I go about that? Right now I can enter Hydrogen in the Fuel Type field but it doesn't store the new record in the Fuels table.

How can I get the new value to be stored in the lookup table when the user types it into the main table? I feel like I've done it before but for the life of me I just can't find the answer anywhere.

It depends how you want to do it but typically Iput a little plus or add button which pops up a text box to allow the user to enter the new value.
This then adds it to the table and I refresh the drop down.

If you are working with a normalised database these should only realyl relate on an ID number.