5 year old child started to chew shirt collars or he chews some clothes its his new habit and how can I stop him from chewing clothes.
This sounds to me like it could be a sensory issue, and I'm especially leaning towards that since I see from your other questions that this is something you've already suspected yourself.
We're not here to give medical advice; I'm just throwing that in as trying to treat a sensory issue as a behavioural issue would be placing too high a burden on the child.
Some children need extra oral stimulus. It could be that he is understimulated, and this is something you that'll go away with training (you could for instance let an electric toothbrush vibrate against the skin around the mouth, for most children it should tickle, but some feel very little, and need extra sensory input in order to activate those senses), but it could also be that he simply has a higher-than-usual sensory need, that simply needs to be accommodated.
There are certainly methods for working with changing habit, and you may well try those in parallel. I've elaborated on that previously in this answer to a similar question, but I'm leaning towards giving the child something he can be allowed to chew on is preferable here, to trying to stop the chewing behaviour, as I expect it comes from a need. A toddler-style bite toy, or sugar free chewing gums are things you may experiment with.
If you do wish to seek professional help, this is something a speech therapist will typically be trained to deal with.
You can get stuff that is intended to be painted on fingernails to stop them being chewed ("Bitrex" is one trademarked version). Its harmless but tastes foul. You could try putting some of that on the edges of the clothes that he puts in his mouth. I'm not sure what it will do to the fabric though.
Of course the risk is that he'll start trying different bits of the clothes until he finds ones that taste better. But with luck after a couple of experiences he'll be put off the whole idea.
My son started at this age too to chew his clothes, especially the shirt collar and arm-ends.
Around one month later he started to get his second teeth. We tried to give him more food to chew on, like carrots, and even bought a white flag root like one can use for babies.
We now have an eye on it, every time a new tooth want to replace an old one, we have wet shirt collars again, until we bought a new bag of carrots ;)
(The first changed teeth were the two middlest downside, then he got one by one 4 new back tooth, where were free space before)