Presuming that you are in the US, have a US credit card with a US billing address, and your friend's country is one of the ones listed on Apple's US gift rules, you can send the gift by purchasing it through the appropriate country's online Apple store. You get to that store by visiting the online Apple store, then clicking the flag at the bottom-right of the page next to "Select a Country". Note that country's store will be in that country's language, so you may need to visit the website through a translation tool (such as Google Translate), or if you use the Chrome web browser, it will offer to translate the page for you.
You then proceed with your purchase as normal, just selecting the gift option so you can enter her address as the shipping address. The gift will be sent directly to her.
The transaction on your credit card will reference Apple, and it will be presented in the currency of the country that your friend lives in. For example, if the gift is going to Germany, the transaction will be presented to your bank in Euros. Your bank will convert that into US dollars. Depending on the currency, this means you may pay more or less than the amount shown when you check out. If you are sending the gift to Thailand, for example, US$1 equals approximately 33 Thai Baht (their form of currency) as of this writing. So at checkout, if you buy something worth US$1,000, it will say the total is about 33,000 Thai Baht.
Additionally, your bank will almost certainly charge you a foreign transaction fee. You would need to contact your bank to find out if that is the case, and if so, how much it is. Generally it is 1% to 3% of the transaction amount.
Alternatively, you could place an order through the US Apple Store, have it sent to you, and then send it on to your friend. The issue with this is the product will be a US model. Depending on the destination country, a power adapter may be necessary, and it may have to come back to the US for warranty service, if needed. If it's a computer, the keyboard that comes with it will be the US model, which again probably won't match the destination country. Additionally, you will have to pay shipping charges, and your friend may have to pay customs charges or taxes when it arrives. Having it sent to them from within their own country avoids all of these things.