Classic potty. It is made of non-hazardous material and will facilitate the baby's gradual transition from diapers to the toilet with greater confidence.
Tip: Put the baby on the potty every two hours for a few minutes without a diaper. Try the same as soon as the baby wakes up in the morning or after naps, as digestion often leads to the need for the toilet.
You can give them a toy or a book to keep them occupied, or alternatively, you can sit next to them and read them a book.
Patience and no pressure are needed until the new habit is adopted by your child.