There are 6 popular methods to intermittent fasting:
1) 16/8 Method
Fast every day for 14-16 hours and restrict your daily "eating window" to 8-10 hours.
2) 5:2 Diet
Eat normally for 5 days a week, and restrict calorie intake to 500-600 on the remaining 2 days of the week.
Do a 24-hour fast either once or twice per week.
4) Alternate-Day Fasting
Fast every other day.
5) The Warrior Diet
Fast during the day, and eat a huge meal at night within a 4 hour eating window.
6) Spontaneous Meal Skipping
Skip meals when convenient. This method doesn't follow a strict fasting schedule. The idea is, skip a meal or eat something healthier when you aren't really hungry in a day.
Read the full article here: https://www.healthline.com/nutrition/6-ways-to-do-intermittent-fasting#section7