Article: Either a handwritten or typed letter is totally acceptable. A handwritten letter will have a slightly more personal look, but a typed letter is better if you're more comfortable that way. What matters is the effort you're making to craft a letter and send it, so don't worry too much about your choice here.  If you choose to handwrite it, use a pen with black or blue ink. Write in either print or cursive, as long as your writing is legible. If you choose to type it, use a font that's easy to read, like Times New Roman or Arial. This is especially necessary if you're writing a thank you letter to a professional colleague. While dashing off a note on a torn piece of scrap paper demonstrates your interesting character, it's considered more polite to use a nice piece of stationery or a thank you card. If someone went to the trouble of giving you a gift, the nice thing to do is send them your letter in a format that shows you're sincerely grateful.  If you go with stationary, it doesn't have to be fancy. Look for heavier-weight paper made with cotton or another high-quality material. It's fine to use stationary with a design or your initials. Packs of thank you cards are sold in stationary shops and drug stores. Consider getting more than one so you'll have more cards on hand for next time. The style of your note will be a little different depending on who's receiving it. Keeping the nature of the gift in mind, think about what type of note would be most appropriate. No matter what, you want to leave the person receiving the note feeling that you're sincerely grateful.  For example, if you're sending a thank-you note to your boss, and the workplace setting is pretty formal, you might want to choose high-quality business stationery, type the letter and format it according to the standards for a  professional business letter. If the note is for a friend, you can show a little more personality. Write your note on a funny postcard, or make your own cool stationary. While sending a thank-you text message never quite has enough oomph to show how grateful you are, sometimes it's fine to send an email. This is especially true if you're not writing the note in thanks for a physical gift. For example, if your aunt lent an ear when you were upset over breaking up with your boyfriend, you might want to send her a thank-you email in gratitude for her patience and understanding.  However, if you need to thank someone for giving you an actual gift or for dedicating a significant amount of time toward helping you, it's better to send a real letter. People realize that it takes effort to write and mail a letter, and that extra time will be appreciated. If you send an email, it should be as well composed and thoughtful as a regular letter would be. In fact, you might want to take even more time making sure it's well written, since you're not going to the trouble of sending it by snail mail.

What is a summary?
Either handwrite it or type it. Pick out nice stationery or a card. Make it professional or keep it casual. Know when it's appropriate to send an email.