Pass a variable on the front end to server after form post

Hi Wapplers,

I have a form that I submit which executes a database insert action however I would like to store another table ID in this table which I can access but can’t seem to send to the server. I can do it via a hidden text input because I get the variable using another action, but this doesn’t seem like an elegant solution. Any tips?

I realise that there is an older post asking the same: