besichtigen= sight seeing besuchen= to visit

Besichtigen means to go to a place to see it and to experience whatever there is to experience like a tourist attraction for example, whereas besuchen just means to visit a place or somebody

I would say that the meaning of 'besuchen' is broader than that of 'besichtigen'. You can use 'besuchen' for family and friends, but also for some places or events you go to with a certain purpose. Kommst du mich im Krankenhaus besuchen? Ich will dieses Restaurant besuchen. Meine Schwester hat gestern ein Konzert besucht. Er besucht noch die Schule. It basically works like a combination of the English verbs visit and attend. 'Besichtigen', on the other hand, can only be used for places you visit with the intention of looking at it. Anything for which you'd use the word 'sightseeing' in English. Also for houses/apartments you're considering renting/buying. Ich will irgendwann das Kolosseum besichtigen. Kann ich die Wohnung schon am Montag besichtigen?

Hii Besuchen is like when you visit someone. (Your family, your friends..) And besichtigen is more when you are sightseeing, like you’re visiting a city, a museum, a famous place.. I hope this helped you :)