Documents for obtaining a patent by a foreign citizen may be submitted within 30 calendar days from the date of entry into the Russian Federation without paying a fine for violating the deadline for applying for a patent.
A patent is issued to a foreign citizen for a period of one to twelve months. The validity period of a patent may be extended repeatedly for a period of one month or more.
As a general rule, the deadline for registration of a foreign citizen for migration in Russia is 7 working days from the date of entry into the country (Part 3 of Article 20 of Federal Law No. 109—FZ of July 18, 2006 "On Migration Registration of Foreign Citizens and Stateless Persons in the Russian Federation").

Foreign workers in Russia are required to pay taxes. These obligations relate to income from work, as well as from ownership of property or transport.

For violating the deadline for applying for a patent or work permit, a foreign citizen faces an administrative fine, not deportation.
According to Article 18.20 of the Administrative Code of the Russian Federation, violation of the deadline for applying for a patent entails a fine in the amount of 10 to 15 thousand rubles.
In case of loss, including due to theft, of their personal documents, including their passport, a foreign citizen is recommended to contact the territorial body of the Ministry of Internal Affairs of Russia at the place of loss (theft) or discovery of the fact of absence of documents.

Starting from January 1, 2025, in accordance with Article 5 of Federal Law No. 115-FZ (as amended by Federal Law No. 260-FZ of August 8, 2024), the period of temporary stay in the Russian Federation of a foreign citizen who arrived in the Russian Federation in a manner that does not require a visa may not exceed ninety days in total during calendar year.
In this case, the continuous period of temporary stay in the Russian Federation of the said foreign citizen may not exceed ninety days. Thus, foreigners entering the country without a visa have the opportunity to stay in Russia for a total of no more than three months. After this period, it will be possible to enter the Russian Federation only in the next calendar year.
The new rules do not apply to foreigners residing in the Russian Federation on the basis of a residence permit, temporary residence permit, including for the purpose of education, as well as those who are in the period of validity of a patent, refugee certificate, work permit and temporary residence permit, including for the purpose of education.
Citizens of Belarus and South Ossetia can also stay in our country for more than 90 days.

Article 33. Requirements for citizens (foreign citizens, stateless persons) entering military service under a contract
A citizen (foreign citizen, stateless person) entering military service under a contract must be proficient in the official language of the Russian Federation, as well as meet the medical and professional psychological requirements of military service for specific military accounting specialties. To determine the citizen's compliance with the established requirements, a medical examination and professional psychological selection measures are carried out.
Types of medical policies in the Russian Federation Regardless of the purpose and from which country a foreigner comes to the Russian Federation, he must have medical insurance. A separate document is responsible for this – a medical insurance policy.
There are two types of medical policies:

Compulsory Medical Insurance Policy (CHI);
Voluntary medical insurance policy (VMI).

But there is a difference in what each of the policies gives to a foreigner and who exactly can issue which one.

VMI policy
A VMI policy is a basic policy that must be obtained by any foreigner entering the Russian Federation. A foreigner must have a VMI policy from the first day of their stay in the Russian Federation. That is, you can apply for this document either before arriving in Russia, or on the first day of your stay in the Russian Federation. The policy should be available not only for adults, but also for children.
If a foreigner has not issued a VMI policy within the specified period, he faces a fine of up to 7 thousand rubles.

Compulsory medical Insurance Policy for foreigners (RVP residence permit)
Every foreigner who is in Russia must have a medical insurance policy in order to receive assistance if necessary. Most foreigners have the opportunity to conclude only a voluntary health insurance contract (VMI). But there are categories of foreigners who will be able to apply for a compulsory health insurance policy if: they permanently reside in Russia and have a residence permit.;
They temporarily reside in Russia and have a temporary residence permit.;
They are citizens of the EAEU and have an employment contract with a Russian organization.;
They have received a refugee certificate or a certificate of temporary asylum, or a certificate of consideration of an application for recognition as a refugee.