Your can easily manage TXT records for by logging in to your cPanel and navigating to Domains → Zone Editor:

To create a TXT record, click on Manage next to your domain:

Next, click on the Add record option and select the TXT record type:

Enter the desired record values and save the changes. After these changes, allow up to 24 hours for DNS propagation to complete and then your TXT record will be fully functional.

Once created, you can manage the TXT record on the Zone Editor using the following buttons: