Stock market

Can we make share purchases immediate for any orders instead of a waiting period

Shares trading is ongoing all the time. 24x7.
to sell your shares, you need someone to purchase them.

if there are buyers, shares are selling immediately.
if not, you need to wait for a buyer.

So I tried to buy shares and they were on the market orders for more than 3 months

Generally to buy stock you need a player to sell it. Most players make sure to control it so only their entities buy what they sell. So you really are not going to have much luck just placing orders.

This should answer your question.

In case you are trying to purchase shares that are offered on the market,
look at the offer price or just buy at market price.