I am in Italy

An "Ehefaehigkeitszeugnis" is a certificate of no impediment to a marriage. It is issued by her (ex-) home town's "Standesamt" (family register).
To apply, she needs to submit
- her valid passport
- her "erweiterte Meldebescheinigung", which is a detailed excerpt from the register of residencies, showing that she is or was registered in that town. If she doesn't have one yet, she can get this at the "Einwohnermeldeamt" (registry of residences).
- her birth certificate or notarized excerpt of the registry of births (available from the "Standesamt" of her birth town).
No documents from you are needed, as it only certifies that SHE is allowed to marry, not you.

Thanks so much for your help thanks

They not give her the Ehefähigkeitszuegins they said they would have to check my documents for about six months and they will take it to Nigeria to be proven Frist before they can give to her

This is unusual.
If their decision was given to her in writing, she can appeal (or sue) against it.
Or you just wait.

This makes no sense. She gets the documents from German officials if she is unmarried and thus able to marry. This has nothing to do with her potential husband or where he is from. But for them to recognize the marriage they would first require a similar document from the husband and if he is from Nigeria then it must come from Nigerian officials. This is then a matter of dealing with getting documentation to present to the German offices, not to get a statement from them.

Tom, I agree with you that it makes no sense - but I know from dealing with German officialdom (not least the family registrars), that their rules are often non-sensical and they tend to make things especially difficult for foreigners.
Their asking for HIS documents to process HER Ehefaehigkeitszeugnis is probably unlawful, so you do have the possibility to challenge it in court. But since this takes a lot of time, nerves and energy, the easier solution is to just give them what they want. The marriage should not start with a fight!

Thanks so much I am just tried this german people are just something else they are not the one conducting the marriage I can't really understand why they need my documents and to prosess it for six months why my marriage is surpose to hold this week I don't just no what to do please help me out please thanks