The rules of this forum require that I can't give you a direct answer to your question unless you have demonstrated some attempt at answering it yourself or at least explaining your thinking. I am surprised that you appear unable to get started on this because a simple Google of covalent bonding will get you started and give you several lines of enquiry to follow up. However to help you get started I am attaching a link which will certainly get you going in understanding more about bonding appropriate for high school level.
In addition to learning about the main types of bonding you can also use the menu in this link to explore intermolecular forces (sometimes called Van der Waals forces) which has direct relevance to your posed question about whether pure covalent bonds can be polar in any sense.
Please do come back to this forum when you have studied the information in this link if you then have further questions.
https://www.chemguide.co.uk/atoms/bondingmenu.html