The following documentation is required to apply for a German business visa

• A passport must be valid for at least three months.
• Two passport-sized pictures.
• Completed visa application form
• Proof of sufficient funds to cover your stay in Germany and return travel.
• Travel insurance worth £30,000
• If you are visiting Germany on their behalf, please include a cover letter from your company.
• A letter of invitation from the company you will be visiting, including the location’s address and the dates of your visit.
• A letter of approval from your employer authorizing your business trip and a power of attorney from your firm granting you complete authority.
• Evidence of prior business interactions between the two organizations.
• The most recent three-month bank statement of the company.
• Income tax returns for the last three years.
• The company should provide a statement of coverage in the letter or invitation.
• Proof of accommodation.
• Proof of citizenship.

You can apply for a visa from 3 weeks before your trip to 6 months before your vacation. The German Embassy or Consulate in your country of residence should receive your application.