Formal:
* J'aime écrire. (This is the most direct and literal translation, and is suitable for most situations.)
Informal:
* J'adore écrire. (This emphasizes your strong liking for writing.)
* J'aime bien écrire. (This is a slightly more casual way to say you like writing.)
* J'aime beaucoup écrire. (This means "I like writing a lot," and also emphasizes your enjoyment.)
More specific:
* J'aime écrire des histoires. (I like to write stories.)
* J'aime écrire des poèmes. (I like to write poems.)
* J'aime écrire des lettres. (I like to write letters.)
You can also use verbs like "adorer" (to adore), "apprécier" (to appreciate), or "aimer beaucoup" (to like a lot) to express your fondness for writing.
Remember to choose the expression that best suits the context and your intended level of formality.