"Foreigner-friendly" means residents of any nationality can apply. It does not tell you whether international residents live there right now. To find houses where they actually do, narrow down to houses with international residents, or to houses where 30% or more of residents are international. Both are based on the resident data that the operators register.
Daily life varies a lot between foreigner-friendly houses. In some, people chat in the shared spaces every day. In others, residents just say hello when they meet. If you prefer some distance, look at houses where residents keep to friendly greetings. If you want a social home, try houses where almost everyone socializes or houses with frequent parties and events, so the house matches what you expect.
When you apply as a non-Japanese resident, you may be asked for your passport and residence card and to pass a rent guarantee company's screening. Some houses also require conversational Japanese. Each house lists its requirements under "Move-in conditions" on its page, so check them before you send an inquiry.