formatting alternating rows

[Joe]

Autoformatting may be the easiest way. Select Format,
then Autoformat. There are a couple that have alternating
gray/white rows.

 

[JMay]

I prefer using Conditional Formatting...
Example, Click on Row-Header 5 select CF, then Formula IS and insert
=MOD(ROW(5:5),2)=1; then Pattern Gray, OK, OK...
Use Format Painter to duplicate downward as far as you want..
HTH