how create aif in dynamic365

If any one know about ax7 could u plz send me the step by step process of

documents

Step for what? AIF was a framework created by Microsoft. You could use it for many things, but you didn’t create the framework.

Anyway, AIF doesn’t exist anymore. The place in documentation you should start with is Service endpoints.

If your question should have been how to create something like an AIF document service in AX 7, you must create a data entity (if there already isn’t a suitable one). If you just want to export data to XML, you can use data management. If you need a web service, create the entity as public and consume it via OData.