What is the most effective weight gain pills for...

What advice should be followed to gain weight?
There are many tips that must be followed to gain weight, but you must make sure that there are no health problems that cause weight loss, such as hyperthyroidism, and it is advised to:
1. Consult a dietitian to do the necessary checks for you and then make your own diet program
2. Eat many Calorie-rich meals with eating some types of food between meals
3. Drinking plenty of fluids
4. Avoiding stress, anxiety and overthinking
Are there vitamins to gain weight?
There are some supplements and vitamins that can be used, including:
1. Vitamin A
2. Omega-3
3. Vitamin B6
4. Vitamin C.
5. Vitamin B1
How to take previous nutritional supplements?
Depending on the type that you are going to use, you can use two tablets per day
Advice ?
Follow the previous advice