I presume it means 'to take on' and would thus translate the sentence as follows:

We need this information in order to take you on as one of our suppliers.

Ich nehme an, es handelt sich um verschiedene Informationen, die im Einkauf oder in der BUchhaltung erforderlich sind, um erforderlichen Daten EDV-mäßig erfassen zu können.

Ah yes ... now I'm with it. Have seen this use of anlegen before in this context. The equivalent in English is 'to set something or somebody up'. So I was wrong about 'taking on' and it should instead be:

We need this information in order to set you up as one of our suppliers.