You cannot and should not flush paper towels as paper towels are not designed to break down in water like toilet paper is and can cause a clog in the toilet and sewer line.
I have accidentally flushed a single paper towel before but thankfully it went down without issues but after I realized I flushed the paper towel I flushed the toilet a few more times to help clear it out of the sewer line.
I don't make a habit of flushing paper towels as it could clog the toilet so you should always just throw the paper towels in the trash can instead.
After using toilet paper you simply throw the toilet paper into the toilet and flush it down along with your poop.
Toilet paper is meant to be flushed and breaks down easily in the water and sewer system and as long as you have good plumbing and good sewer lines and don't flush too much toilet paper at a time the toilet paper should cause no issues with your toilet or sewer lines.
Some people prefer to throw the toilet paper in the trash can but that is actually not sanitary with poop or blood etc on it.
Toilet paper should always be flushed down the toilet and if your toilet can handle your poop just fine it can handle the toilet paper as well.
Toilet paper is designed to disintegrate and break down in water and once flushed it should be nearly fully broke down.
Wipes and paper towels however are not meant to break down int the toilet and can cause clogs.
So paper towels and wipes should be thrown in the trash but toilet paper can and should go into the toilet and into the sewer system or septic system.
Toilet paper is also safe for septic systems and will do no harm as long as you have your septic tank pumped out often enough.
However thicker toilet paper takes a bit longer to break down but thinner toilet paper breaks down much faster.
I've always thrown toilet paper in the toilet even at peoples houses that told me to throw it in the trash.
I'm not leaving my disgusting poop covered toilet paper in someones trash and not even my own trash.
In the toilet the toilet paper goes.