Life coaching is structured around 60-minute coaching sessions. As a general guide, they start with the coach getting to know your story. Step by step, things are broken down to provide specific and actionable solutions. Coaching sessions generally use various tools and techniques from life coaching and neuro-linguistic programming (NLP).
If you're more specifically looking to make a change to your habits then we will be working on a lifestyle change, not something that we can fix overnight. Not 21 days, not even 30 days. There is no finish line here because this is something you pick up for the rest of your life. This doesn't mean you need a coach like me to accompany you and hold your hand for the rest of your life. No. It means you need to be totally in to make this change last forever. If you're not really ready yet to commit to that there's no point to start to work on a habit change with in the first place.