For personal loans ranging between 1.000,- and 25.000 Euro, which is the most common amount for credit in Germany, you will need to have
a monthly net income of at least 600,- Euro
a permanent residence and address in Germany
identification documents (passport or ID-card if you're a EU citizen)
mobile phone number and email address
Furthermore, a clean credit history is recommended, otherwise your options will get a lot narrower and interest rates increase.