before start How to add Google verifition code in CWP . You must need to know how to open DNS Zone editor , Please take a look from below link
when you click on add Type record you can see a a list will come you need to select on txt ( text )
Ten you can see a box will come You need full
Record Name : yourdomai.com. ( end with .[dot] 0
Cache: leave it blank
and click on Save record button .
Please take a look screenshot below .