You have to reach out and network. Networking is a critical skills for any career.
As @thumper1 suggested, start by asking your own physicians and any family friends that are physicians. if they can’t accommodate you, ask if they can suggest someone else you can ask.
Some health professions advising offices maintain list of local doctors who have allowed students to shadow them in the past so be sure to check with them.
But the most common way students find doctors to shadow is through their clinical volunteering activities. When you are volunteering at a hospital, public clinic or other clinical site, let your supervisors and any doctors whom you work with that you would like to do some shadowing. Doctors are much more likely to allow someone they know to shadow them–esp. if you have already demonstrated appropriate behavior around patients and medical professionals.
The AAMC has some great tips about how to go about finding shadowing opportunities here:
Every clinical site will have health and safety requirements for visitors that you must be willing to meet. These include wearing a mask and being vaccinated for Covid.
Be aware that Covid has changed the willingness of many physicians to allow students in their practices due to the risk of exposing patients unnecessarily to those not directly involved in their care. Expect to get a lot of "no"s before you get a yes.