1. Log into the domain control panel ( if you are using domain's free DNS ).
  2. Click DNS settings on the Advanced settings tile.
  3. Go to DNS records.
  4. Under create a new record, click CNAME.
  5. Enter the following details: Example -  We have to add _f0c4f170e07f266ad4865d79636f2e4b.domainname.com CNAME 036581d906c05a9fadc557ae6437d08a.287b6fc27b49336d0a4c149ac1e26d56.t0887220001585286318.comodoca.com 

Here you have to notice 2 value - Hostname / TXT & Value/Alias


The hostname will be ( do not copy .domainname.com )  - 

_f0c4f170e07f266ad4865d79636f2e4b  


Value/ Alias - 036581d906c05a9fadc557ae6437d08a.287b6fc27b49336d0a4c149ac1e26d56.t0887220001585286318.comodoca.com


TTL ( second ) - 1 ( or as less as possible )


Click Create/Save the record to save your settings. Wait for 10 to 30 min of DNS propagation. The time it takes depends on your domain host. In general, DNS changes are processed and propagated within 2 hours, but sometimes it can take up to 72 hours.  



HOW TO CHECK CNAME IS CORRECTLY ADDED OR NOT?


GO TO WEBSITE MXTOOL - https://mxtoolbox.com/CnameLookup.aspx 



ENTER CNAME WHICH YOU WANTED TO CHECK. EXAMPLE AS FOR ABOVE - 

_f0c4f170e07f266ad4865d79636f2e4b.domainname.com


IF WEBSITE RETURN VALUE ( WITH GREEN ) MEANS ITS ADDED IN RIGHT WAY. Like -