I want to do ssh is from outside the network. But I'm unable to do it. Very much frustrated. Has anyone tried it successfully?

Yes, wayyy too many times to count

@netikras please guide me. It would be so helpful for me

Is this a home server/computer where you can access the router? You could set up port forwarding there.

To access your router's admin panel over HTTP, check the bottom of your router or the manual for an IP address (like 192.168.1.1 or whatever shows up as the 'Default Gateway' in network settings on the device), or just google your router's brand/model + 'admin panel ip'. Also, see if the router has a username and password on the bottom or just google router's name + 'default password'. (might be admin/admin, admin/password, or admin/<blank>). Maybe comment your router brand so that we can give more detailed instructions.

@Allan I have tp-link router and I have accessed my router on 192.168.1.1 too. But I don't understand what should I give new port no?

Have a look at https://tp-link.com/us/... . Internal port would be 22, protocol TCP, and internal server IP would be the internal IP of the computer that you want to connect to. Common Service Port may have a preset SSH. External port can be whatever you like. Maybe not 22 as port scanners will look for that. Pick a random high port number if you can.

@aarfa Another thing to do would be to reserve an internal IP for the ssh server. Some instructions for that can be found at https://tp-link.com/us/... . You will probably also want to set up Dynamic DNS with a provider like https://www.noip.com/ so that you have an easy to remember hostname like aarfa.servebeer.com that always points to your IP address. Some tp-link routers support Dynamic DNS (https://tp-link.com/us/...), but no-ip also has Windows, Mac, and Linux update clients so that your domain is always pointing to your IP address.