>How can create a button in a form to delete the record
>of a table where I am at that moment ?

Assuming you have buffering, the code would be similar to this:

delete
if not TableUpdate()
  MessageBox("Não posso apagar o registro!")
  * Further analysis with aerror()
  return
endif
skip
if eof()
  go bottom
endif
ThisForm.Refresh()

I strongly recommend that you use buffering; however, if you don't, omit the part from if not TableUpdate() to the corresponding endif.

Also, many programmers who are relatively new to VFP are tempted to PACK at that moment; don't do this: it is slow, and doesn't work on a shared table. Instead, use SET DELETED ON to hide deleted records; do the PACK once a month at midnight, with a special maintenance program.