I have a small problem with SharePoint. I customised my list in InfoPath and as you can see on first picture a Passport TextBox has 100% Width and is properly stretched from left to right side of my table. However, in SharePoint width of this TextBox is visibly decreased. I don't know why SharePoint is doing that. Changing font size, TextBox width and other action didn't resolve my problem.
In InfoPath, the table cell and the text control are two different objects. Each object has its own width setting.
It can be quite tricky in InfoPath to select and format the text object instead of the containing cell object.
On top of that, any table cell in InfoPath can have padding settings that can impact the text in the cell. This is especially pesky and persistent when you use one of the Infopath template layouts.
So, in Infopath you need to check the formatting for the immediate text control and all the containers that surround this control.
It can be tricky, but it can be done.
If you are struggling, please share a sample file with a file sharing service for inspecction.