I've sold a fair bit recently. You need to price competitively otherwise it will sit there unsold.
On Vinted barely any of your stuff is worth what you think it is and you will get offers that are much lower than your asking price. It's best to view it as decluttering and any cash made is a bonus.
An example of something I've sold - unused eyeshadow palette RRP £60 put it on Vinted for £15 sold via an offer for £10. I didn't expect to get more than £10 but if someone bought for £15 that's just a bonus.
The buyer pays the postage and they can choose from all the options you have specified in your profile. I advise turning off the Royal Mail option as I don't think it is yet integrated into Vinted and can result in more scams. Also check what you have nearby for courier drop offs. No point offering Evri if your nearest drop off point is 15 miles away and it's difficult to get there.
I package everything very securely even if it's a low cost item. I reuse packaging where I can but also have a backup of mailing bags, small boxes and bubble wrap from Amazon.
My understanding is that you can usually get a slightly better price for things on eBay but I find Vinted more convenient to use.
If everything goes swimmingly then Vinted is great but if something goes wrong they are worse than useless. Customer service is all AI bots and it can take weeks for a human to look at complaints from either side. Even then there's a strong chance you'll just lose the sale and be left with nothing. For that reason I wouldn't sell or buy anything on there over the £50 mark which is my line for the amount I'm prepared to lose (your line may differ).