Who can see the changes I make to the quote/invoice table columns?
On both the Quotes and Invoices page, you can hide and show table columns by using the button at the top of the page, shown here.:

Temporarily Change Your Layout
You can modify your table columns temporarily by making your desired changes, and then clicking Apply Changes. This will affect the view within your own profile only - not the entire team's. Your new layout will last until you navigate away or refresh the page, and then things will revert to how they were previously.

Change Your Layout Long-Term
If you would like to change the column layout long-term, then you can click the Save Columns as Default button. Doing this will change the layout for yourself and all others users in your Paycove account - whether or not you are an admin - so be mindful before making this selection.