Trigger a task manually via an prominently displayed action

[frogbean]

Hi folks

I would like to trigger a pdf on change of a column, via a standard 'on update' bot, but I can't get the column to be editable, see below. I can't tell why, as it's not ref'd in sub-tables, it's not a key, it's not a label. If you can answer that, great.

So in the meantime I'm thinking ok, if a user makes a change in the database (excel in this case, I know, I know, they should be using the app only but client's old habits die hard), they can see that change reflected in the app, then manually generate the pdf to reflect that change. However, the actions that I can set can't be linked to an existing task. 

Is there any way to do this? The 'send email' action doesn't allow for attaching a pdf. 

Thanks in advance! 

Chris