How to fix my leaky toilet, its leaking at the place where the water goes into the tank.?

After messing around with the connection a bit, it still leaks. Do I just need to take apart the connection and put new washers or whatever there. Or can I just get some teflon? tape and put it over the seal on the inside?

If youre going to do it do it right then sit back & relax.
If youre not moving anywhere soon just get it over with.
Experienced plumber or home DIY approx 2-3hrs depending how many trips to the store ya make. lol
1 st turn water off, shop vac the water out of tank dont waste all day with a sponge, buy a toilet rebiuld kit approx $15 or less for all parts together or seperate. Dont forget new tank to bowl bolts.
2 nd Upgrade to a fast filling easy to install & adjust hush flow valve it will be worth you time & $9.00 spent.
3rd yep replace that wax ring with a forever ring.
4th install a braided hose valve to tank.
Now you wont have to mess with the toilet for several years.
Let me reassure you if one rubber gasket is rotten they all are.
Replace the tank to bowl donut with a chemical resistant one if you use tank drop ins which is a no no.

If you are "messing around" with plumbing, you are most likely in for something that will ruin the next ten minutes of your life. The fitting needs to be tight enough but too tight and things can break and it's not possible to cover all the possibilities in a short paragraph. Normally, you needn't replace the rubber seal (if there is one--sometimes they are built in) and tightening it a bit will stop the leak but don't get ham-handed on it.

teflon tape. around the female end of connection.
may need a new toilet.

sounds like the rubber washers are bad change them and make sure its a good tight fit.

Plumbing is always a pain. you can try to mess with it or replace the parts, but to be honest, a reliable plumber is worth the money and the hassle. 30 bucks for some piece of mind? You make the call...

I just fixed mine and it's not bad at all.

If you've already tightened it down pretty good and it's still leaking, you'll probably need the new washer.

I bought a kit at the hardware store, and was pleasantly surprised at how easy it was. Talk to your hardware store guy, they love this stuff.

You can do it!

It probably is just the rubber washer, but since you have to take the whole thing out to replace the washer (it is on the inside of the toilet) you might as well replace the whole assembly. You can buy a replacement at any local hardware store for about ten bucks. As long as you are there, spend and extra few bucks and buy a flexible stainless steel hose to connect the toilet to the valve. The flexible hose makes the connection so much easier and you don't have to worry about bending (actually crimping) the supply line when you are working on the connection.