The requirements of the partner banks differ from country to country: Depending on the regulatory requirements in the respective country, the contract is usually made through an electronic application via your online banking. You can also upload the account opening documents directly in the online banking of WeltSparen.
The partner banks also need a copy of your ID, which you have already given WeltSparen as part of the identification process (Postident or Video-Ident), but you can also upload your ID in via the online banking if you are asked to do so after choosing an offer. As a rule, the partner bank needs your identity card to open. If a partner bank explicitly needs your passport, you will find this information together with any other document requirements in the respective product information sheet.