Prevent excess formatting in Excel pages ...

I create simple analytic quarterly income and expense pages for a local charity's annual accounts using Excel.  I format columns and rows with fill, formulas and various text options, by selecting the whole row from the left or column from the top.  

Each page extends only up to approximately 20 columns and 60 rows.

How can I 'contain' these rows and columns to define and restrict the size of the page before selecting a row or a column?  The instructions to 'remove excess formatting' do not seem to work on my Android laptop ...

Thank you!