Why stoploss is compulsory in BO order?

Is there any option to enter trade with also setting exit price ?(Target Price)

In BO order we have to enter stoploss too.

Bracket Order is incomplete without any one of the legs, you cannot just use Target and not use Stoploss.

Is there any restriction by exchange or SEBI for this feature ?

It is because, first of all the idea behind Basket Order is to make the trade completely automated.
And one of the big reasons is high leverage with low margin required. When you have a stoploss and Target this, reduces the risk indefinitely as you have guaranteed your boundaries and have lowered the risk taken by the brokerages offering you that leverage, Essentially it decreases the brokers risk of margin call.

Zerodha offers target feature for CNC order. Why don’t you add this feature in MIS ?