Amputation of a toe other than the big toe, including removal of the metatarsal head.
To support a 20% rating, your records need to show that the amputation included removal of the metatarsal head. Surgical operative reports are the most direct evidence of this, because they describe exactly what tissue and bone were removed. Pathology reports or post-operative notes may also confirm metatarsal involvement. X-rays or imaging taken after surgery can show whether the metatarsal head is absent, which supports what the operative records describe.
For the 0% level, records would show amputation of the toe with the metatarsal head still present and intact on imaging. If your records do not clearly document metatarsal removal, a VA or private examination that reviews the surgical history and current anatomy of your foot can help clarify what was removed. Statements from you describing the extent of your surgery may also help prompt a closer review of the underlying medical records.
Conditions that are often caused or made worse by this one. If you have any of these, they may be claimable as secondary service connection.