No one has time to go to the store every. single. day. I usually do my meal planning on Monday, but Sundays are also a great day to do it. I sit down on a computer and research ingredients, dishes, recipes, and vegetables that are seasonal. I try to create or choose recipes that I know my husband is going to like, otherwise he will go for leftovers. I let my husband choose what dinners he wants for what nights. That may be handing too much control over to your family, so if you want to decide what is going to be on everyone's plate that is fine!
Once I come up with what I want to make and the ingredients then I create a sheet with everything I need at the store that goes with each dish. I also include anything I'm out of- I go through almond milk like it's no one's business! If I forget something at the store then I try to just use what I have on hand, because I try to not go to the store constantly. I also want to save money and not overspend on recipes.
Now, I don't make my meals ahead of time on Sunday nights, but some people like to do this as part of meal planning. They will choose a certain meal they want- Broccoli, sweet potatoes, rice, and beans (for example), and then make a huge batch of that on Sunday night. Then you can put the food in containers and spread them out evenly for each night of the week. I personally get bored eating the same thing for dinner, so I would choose two to three different kinds of meals to make ahead so that I have a different option each night. This makes life easier if you have a grab and go lifestyle!
If you are going to try the method of making everything ahead of time then prepare yourself for about two hours of cooking on Sunday night.
If you want more recipes that are based on a slow cooker or instant pot then I recommend chopping and preparing all of your ingredients on Sunday night. I put them in bags and label them and then I just drop them into the crock pot or instant pot and let them cook all day. I find that it's easier to come home and just dish everything out. The best part about doing this method of meal prep is that you can still have things like tacos, soups, sandwiches, stir fry.. etc. and everything tastes really fresh instead of it being warmed up.