Freezing up can be caused by many things. Low refrigerant is only one possibility. Among other possibilities, low air flow is a common cause, and restrictions in the refrigerant line somewhere can also cause it.
Try checking your air flow (proper fan speed, clean filter, open air belts/ floor registers, unobstructed return air grills, clean evaporator coil fins, etc...). Those are the easiest possibilities. If you have just recently changed to a high efficiency filter then that may be the source of your issues, if it worked fine before then no need to change back, but if it occurred after replacing with a high efficiency filter then toss it and use a standard low efficiency filter.
Turn the cooling off and run the fan for an hour or two so all the ice has a chance to melt before turning it back on. Ice restricts the airflow and only causes itself to ice up again if not resolved. While the ice melts you can check all the other airflow related suggestions I made.
What is tour outside temperature? It might be too cold outside to operate your cooling. There are ways you can make it work but let’s diagnose the issue first so we know if we even need to go there.
You need to have an access port on the big pipe (suction pipe) also to check your charge, or to charge your system properly. It’s probably located inside the condenser somewhere. Don’t worry about that right now.