is it allowed to eat standing, sitting on chairs in Hotels, or now a days parties are arrange to sit on chair without taking out shoes?

As a Muslim, the only way to lead a life is the one spelled out for us by Rasuallah salallah alhe wa sallam. It is reported by Abu Hurarath RA that Rasuallah salallah alhe wa sallam said, Whosoever obeys me, has obeyed Allah. Whosoever disobeys me has disobeyed Allah. To eat whilst sitting on a chair is against the sunnath. It is reported by Hazarat Anas RA that Rasuallah sallallah alhe wa sallam would not eat on a table. If in a certain place it is the specific trait of kuffar and fussakh, then one should make an extra effort to refrain from it completely.

It was narrated that the Prophet (peace and blessings of Allaah be upon him) used to eat (sitting) on the ground. It is also narrated that Rasulullah [sallallaahu alayhi wasallam] said, "I eat as a slave eats and I sit as a slave sits." To eat whilst standing is against the sunnath. The Prophet Sallallah Alhee waSallam encouraged us to take off our shoes before we eat so that we may be comfortable. It is permissible to eat with one's shoes on. (Ibn Majah P. 236, Ibn Majah P. 2, Fataawa Mahmoodiyyah V. 5 P. 117, Ahsanul Fatawaa V.8 P. 111, Abu Ya'laa V P.318)

If one is faced with a situation of eating on a table and with shoes on, one should not adopt a specific way adopted by the Kuffaar in that, for example, two people eat in one plate, etc. That type of change will be sufficient to come out of the ambit of imitating disbelievers.

and Allah Ta'ala Knows Best

Mufti Ebrahim Desai