US/CANADA applying for PhD advice!!

I'm a masters student currently my area is pharmacology ans right now its September and my thesis will complete by June or July 2027. My CV is ready i have shortlisted universities of both US and Canada i dont have an agent yet. But I'm emailing the professors and sending CV and by Dec and nov will start applying for sept intake next year. I really need advice on what go do for visa and other tips if you have for me!! I really need help even though I'm working i feel so lost and overwhelmed and stressed!!