I wanted to change the tyre but the tyre is not inflating properly I tried with 3 different tyres what might be the problem? Is there any chance of rim damage or alignment problem.
I assume you have tyres with a reflective strip or some other marking on the sidewall and you can see that it’s not radially symmetric, with more or less sidewall visible in some parts as you go around the rim.
This usually means that the tyre bead is not properly seated in the rim’s hooks. You can often solve it by inflating to the maximum pressure of your tyre (or even slightly above). Around 3 or 4 bar they tend to just pop into position. Of course release air to your desired pressure after doing this.
But first make sure the tyre is actually properly installed and the tube (if you are using one) not pinched between tyre and rim. I prefer to inflate to a very very low pressure and go around the rim, pushing the tyre away from the rim and checking that I don’t see the tube between rim and tyre. Often this is also already enough to seat it properly.