Creating an Accessible Illustrator document

Good morning, 

I am having some confusion on how to produce an accessible document from my Illustrator tool. For example, in any Microsoft Office tool (word, powerpoint, excel) I can run an accessibility checker to make sure that I have added alt text, heading structure, etc. By doing this I am ensuring that the document is accessible before I make it a PDF. However, in Illustrator I am only to add alt text after slicing the object, but I can't add any heading structures or tags -- not that I can see anyways. Will I have to export my Illustrator document to a PDF first and then go to the PDF after and add tags to ensure that it is accessible? I am just trying to figure out the correct procedure. 

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