Is it true that representatives of pharmaceutical companies come to doctors and offer doctors, on a commercial basis, to prescribe their medicines to patients?

Yes, it's true, only it looks different and more legal. Pharmaceutical companies organize free seminars for doctors with all kinds of bonuses (certificates, gifts, etc.). At these seminars, firms advertise in every possible way, promote their products (you must have seen calendars, pillows, cups at doctors' offices).

Article 74 of the Federal Law "On the Basics of Health Protection of Citizens of the Russian Federation" prohibits medical and pharmaceutical workers from such activities only if it is not about conducting clinical trials of a new drug. However, laws are often not enforced, and some doctors do not even know about the existence of such a ban.
Pharmaceutical representatives often come to doctors - advertisers, telling about the merits of a new drug. They also sometimes bring pens, stickers, booklets, invitations to conferences, but they do not require their prescription.

Not entirely true, but it is difficult to call it a lie. Pharmaceutical companies don't run their representatives around doctors. They act smarter - they conclude an agreement with the Ministry of Health on the supply and use of their drugs. Further, the Ministry of Health in its instructions "recommends" doctors to prescribe this or that drug for treatment and report the results.