The easiest way to access censored websites and apps in Russia is to connect to a VPN. Short for Virtual Private Network, a VPN encrypts your device's internet traffic and routes it through an intermediary server outside of Russia. VPNs are typically subscription services that cost a few dollars per month. By installing a VPN app on your computer or smartphone and connecting to a server, you can bypass government restrictions and freely access the web.
The Russian government maintains a blacklist of URLs, domain names, and IP addresses that internet service providers must block by law. The list originally focused on sites that contained materials related to drugs, suicide, and child pornography, but has since been expanded to include content that criticizes or undermines the federal government.
You can find our list of the best VPNs for Russia here. In 2017, Vladimir Putin announced Russia would ban the use of anonymous proxies including VPNs and Tor. That being said, the only effect so far seems to be that VPN websites are blocked in Russia, but not VPN traffic. To that end, make sure you subscribe to a VPN before entering Russia, and choose one with strong security and a strict no-logs policy.