of course the first place to start is visiting friends, neighbors or relatives. your parish or diocese probably has a ministry for both visiting the sick and visiting the imprisoned, and can answer those questions for you. They can also help you comply with rules, that in this modern day society, govern such efforts. For instance in most cases you simply won’t be allowed to visit prisoners without some kind of authorization, and if you represent a church, some kind of training. In our area anyone of course can visit friends or relatives in the hospital or nursing home, but there are rules for who is allowed in any facility as an actual chaplain, or to bring communion to the sick
. In the meantime, visit those you know, when you are allowed and simply visit with them as you would in other circumstances. Supporting such ministries in other ways is also part of carrying out these works of mercy. For intance, our school children who would not be allowed in many hospitals or nursing homes, except to see relatives, make gifts for patients and residents, which are carried to them by those who do take communion to the sick.
there are also plenty of people sick in their own homes who could use a visit, someone to shop and run errands for them, someone to care for children of a new mother or someone recovering from surgery, someone to do yard work etc. Also plenty of people who would come to church if they had a ride.