Upvote:2
A job seeker visa for Germany cannot be extended.
You have 6 months to either find a job or return to your home country, from where you can apply for a new visa but it will be tougher to obtain.
Normally in order to then get a secondary job seeker visa, you would have to show that you have improved your skills in some way which had previously stopped you obtaining a job. e.g. more training, qualifications, or improvement in your German language skills.