I got this from my internet provider: 

We have received notices about an open service/port at your IP address, which may enable third-party use by third parties. This is often due to the die
Adoption of a standard configuration or retention of the delivery state. Please close this vulnerability and check your devices, It is not only your devices and data that may be damaged, but also other customers on the internet. For this and for any consequences, you can may be held liable.

And the open ports I have are: 21/ftp, 22/ssh, 23/telnet/53/domain, 80/http, 443/hhtps, 8082/blackice-alerts, 20005/btx.

If I have an idea for a couple, I don't for most, certainely not there signification.

Would you help me with clarifying what are these ports (need, mean) and how to close when I need it.

With appreciation of a response to my question.