Yes, you need a travel adapter (plug adapter) for a trip from the United Kingdom to Azerbaijan. In Azerbaijan, people are using different plugs and plug sockets that are not compatible with plugs from the United Kingdom!
Which types of plugs are used in Azerbaijan?
Azerbaijan uses plugs of type C and F. Plug sockets of type G, which are common in the United Kingdom, are not in use in Azerbaijan.
The frequency, therefore, is the same as in the United Kingdom. That's why it is safe to use all your electric appliances in Azerbaijan.