I apologise for the delay in replying, I have been on holiday.
For teaching appearance, the most natural language forms to use are:
The verb “to be” e.g. he’s tall; she’s short; they’re fair-haired, etc.
Have / has or has got / have got e.g. she’s got long hair; he has brown eyes.
The verbs “to seem” and “to look” are sometimes used; e.g. she seems cheerful, he looks interesting.
They will also need to know vocabulary such as hair and eye colour; tall, short, slim, large, etc. They will need to know the words for facial features: nose, eyes, etc (they should know this at elementary level).
It doesn’t matter that they don’t know the modal verb “can”, it’s rarely used to describe someone’s appearance.