In our office We have one Wall plug for ADSL cable. But we need two computers to plug in.
If we buy a switch can it will do the job for us and use internet in both computers
You need the following composition:
ADSL Modem + router (normally provided by the ISP as one device) (==> if not provided in one Device: connect ADSL connection to modem, connect modem to router.)
Then connect this device to a switch.
Connect both computers to that switch.
Done
summarize: Modem - router - switch - computers
Yes, a switch would be what you'll need.
Do you already have an ADSL/Cable modem? If not, you can get a modem/switch combo.
So both your computers will plug into the modem/switch combo, and your modem/switch will connect to the internet.
If you already do have one, you can just get a switch, which both your computers will plug into. The switch will plug into the modem, which will connect to the internet.
If what you have is an ADSL Wall plug that is essentially a phone line connection that needs to be plugged into a DSL modem in order for you to have internet access. If that is the case I would use a DSL modem plus a router that has a switch built in, this will enable you to create your own network with you hiding behind a Nat router giving you a little extra proctection. It also will make it easier for you to expand your network in the future.