Non- EU residents must apply for a work visa and a residence permit before travelling to Germany. You must approach the German embassy or consulate in India.
The application for the work visa should have a job offer letter from the firm in Germany, you must also have an annexure for an employment permit, you must provide the certificates of your academic qualification, and also the certificates of your work experience with the approval letter from the Federal Employment Agency.
The Germany Job Seeker Visa is a long-term visa entitling the visa holder to stay in Germany for a maximum of 6 months while searching for a job from within Germany. If you find a job within 6 months, you can apply for a Residence permit or work visa in Germany. There is no requirement to return home and apply for the same.