After Nikah & wedding inviting your close family members, friends and neighbours for a feast is a compulsory sunnah of Prophet (PBUH) which every muslim must follow.
There are certain things which have been added in this simple sunnah which have made it an expensive event. People book expensive halls just to compete with others and invite hundreds of people, even those with whom they haven’t met from years.
The sunnah of walima is very simple, after Nikah the husband invites close relatives, some neighbours or friends and arranges a feast according to his ability.
In many cases the family of women is burdened to pay for the expenses of the walima it is against the Islamic teachings because it is an obligation & responsibility on the husband and not the bride.
But if the family of the bride is more stable financially and wants to help the groom in arranging the feast then there isn’t any harm in it, but pressurizing and demanding is against Islamic teaching.