Can intake sertraline hcl 100 mg at around 6pm or does it have to be taken in the morning?

Medication timing: You can absolutely take it at 6pm. The key with sertraline is to take it at the same time every day.

Does not matter: Some people find this medication to be "activating" and find themselves having a difficult time sleeping if they take it in the evening. Others find that it makes them a little more tired. If it makes you more tired take it at night. If it makes you feel more energetic, take it in the morning. Either way is ok, the most important thing is consistency.