I want to play Minecraft with my sister and i don't know if I have to start LAN world each time we play together.
You should be able to just go into the world you want to play in and your sister should be able to join in the multiplayer tab or, if you're on Bedrock you go into friends and the world should appear in the LAN games and she should be able to join. I'd say your only other option would be to start a Realm (which costs money to rent off Mojang) so either of you can join the world whenever you want. Hopefully i was helpful
I want to play Minecraft with my sister and i don't know if I have to start LAN world each time we play together.
You should be able to just go into the world you want to play in and your sister should be able to join in the multiplayer tab or, if you're on Bedrock you go into friends and the world should appear in the LAN games and she should be able to join. I'd say your only other option would be to start a Realm (which costs money to rent off Mojang) so either of you can join the world whenever you want. Hopefully i was helpful
There's also a public service called Aternos, which hosts free multiplayer worlds. It's very helpful but there are a few downsides:
1. The server will turn itself off if no players are on for 5 minutes, so you'll have to start it up again.
2. Either you or your sister can start it up, but it will still take a few minutes to start.
3. It's only for the computer
https://aternos.org/server/
If you're on the same network/wifi starting lan is the easiest option without paying money or having a PC run the server client all the time