now i can not update macOS catalina via apple store. My macbook air is macbook air (11' 2013 mid). Pls recomment, how to update for me.

Do you have a uSB or Thunderbolt to Ethernet cable, use that to download Catalina as it is an 8GB download and WiFi can be a bit unreliable. Do not use the mac while it is downloading or any other devices that share the internet connection.

You might better describe what is happening. Also, please say which year and model computer you have. Some older models will only accept certain updates or Operating Systems. These are detailed on the Apple Support site, if you need that information.