INCORRECT: I'm learning English for about a year. (Use the present perfect for something that is happening now, for a future plan, or a duration of nonspecific length. You may say, "I'm learning English." This could mean right now in this moment or over a period of time.) CORRECT: I've been learning English for about a year. (Use the present perfect continuous for an action that started in the past and has continued to the present moment and may continue into the future. Keywords: 'for about a year.') Learn more verb tenses at: https://www.englishpage.com/verbpage/verbtenseintro.html

The first sentence is a different meaning. You could switch it to "I am learning English for a year", to make more sense. Depends on what you're trying to say.