In general

An RS must be submitted when the following transactions have been performed:

• the business delivers goods elsewhere in the Community territory
  (intra-Community supply of goods – Section 18a (6) of the German VAT Act [UStG])
• the business makes a delivery within the meaning of Section 25b (2) UStG
  (intra-Community triangular transaction)
• the business provides other taxable services elsewhere in the Community territory, for which the recipient owes the taxes
• the business carries out transport or shipping within the meaning of Section 6b (1) UStG (Call-off stock regulation)

The tax authority’s Elster service portal and the BZSt Online Portal are available to you for submitting the RS. Further information can be found in the "Electronic submission and data transmission" section.