If you are using our nameservers and the TLD supports DNSSEC, there will be an option to activate DNSSEC in the "Our nameservers & DNS" under "Modify Domain Setup".
If you are using external nameservers, you can enter the DS or DNSKey record in the "Your Nameservers" section.
Some TLDs do only support DS or DNSKey records, please make sure to enter the correct type. You nameserver provider should be able to provide both to you.
To disable DNSSEC please click on the disable option if you are using our nameservers. It is located in the same place as the enable option.
If you are using external nameservers, DNSSEC can be deactivated by removing the record the same way it has been added.
Please make sure to always deactivate DNSSEC before you change the nameservers of a domain. If you do not disable DNSSEC, the domain will not be resolving correctly after changing the nameservers.