can I use bit coin to pay my overseas customers
Absolutely! Bitcoin can be transferred peer to peer, to anyone over the net.

Now, you should note that:


Bitcoin is very volatile.
Bitcoin is very congested and slow these days, using litecoin or ethereum may be a better pick at the moment.


Also too, you will need to make sure your oversea customers will accept bitcoin payments. Some countries do not have a online exchange available to cash in bitcoins, so it is very important to tell your customers if bitcoin payments are ok.

tl;dr - yes, you can send bitcoin payments to anyone, in any country as long as they accept it. Then, your customer can optionally choose to cash it at a online exchange available to him for fiat cash.