The verb bid—meaning (1) to offer, (2) to command, or (3) to invite—used to be inflected bade in the past tense and bidden as a past participle. These forms still appear, especially where what’s bid (or bidden) is a hello or a goodbye, but they are fading from the language and may soon disappear. In today’s English, bid is usually uninflected.
For example, these writers use bid in the past tense:
He says he bid for the Valiants because he was impressed by the club’s infrastructure. [This is Staffordshire]
We bid the driver goodbye just outside Old Town about 8 p.m. [Los Angeles Times]
She bid her fellow contestants a tearful farewell. [Stuff.co.nz]
And these writers use bid as the participle:
A proud mother has bid her daughter farewell as she prepares to row 5,000 miles across the Pacific. [London Evening Standard]
Like a vexing houseguest who overstayed his welcome, it was bid a swift farewell. [Mankato Free Press]
He had bid his wife and children – Heather, 11, and Tommy, 8 — goodbye at the hotel. [Billings Gazette]
The traditional forms still appear occasionally (and bade is usually paired with farewell)—for example:
Cardiff Blues supporters bade farewell to a host of players in their penultimate match of the season. [BBC Sport]
Misty-eyed couples bade farewell to their friends and well-wishers. [New Zealand Herald]
I was bidden to the delightful Cruden Farm, near Melbourne and 2000 kilometres away … [Sydney Morning Herald]
These examples were hard to find, though. Bidden is especially rare, at least in current newswriting.
This ngram graphs the use of bid, bade, and bidden in English-language books published from 1800 to 2000: