'전략' means omit introductions in letters or comments. When writing letters, we start greeting and write something about weather and inquiry. But if you or others want the main subjects, '전략' used before main subjects. You can used to friends, teachers and business partners - almost anyone. My English is not good, but I want to help you, so I write some comments. Is it useful to you? If you have any questions, please write comments.^^

前略 is 전략 as a noun. 前 means 'before' and 略 means 'to omit something'. the When you omit the first part of speechs, writings and letters, then you can use, 전략하다. However, it isn't a common word used in daily life. Maybe in some business or educational reports, when you need to indicate the omission of them.