In most cases, Full Planning Permission is not required for a typical garage conversion project in the UK, as long as the work falls under permitted development rights. This means that you can convert your garage into living space without seeking Full Planning Permission Application from your local council, as long as certain conditions are met, such as the conversion not exceeding a certain size and not causing harm to the surrounding area.
However if that’s the case you may then need to apply for a Lawful Development Certificate or a Householder Planning Application if the work falls under PD rights.