Step 1 : Log into your Godaddy account 


Step 2 : Now go to My domains


Step 3:  Click the settings icon and click Manage DNS




Step 4 : Now scroll your window there will be an option called  "Nameservers" and now click change 



Step 5 : Select custom option in the drop-down list



Step 6 : Now enter your Cloudflare nameservers


Step 7 : Now the cloudflare nameservers will be updated.