system
Given the following post, respond as if you're commenting on Reddit:
human
[Doctor Who] Can a TARDIS take any form?

So, the Doctor's TARDIS has taken the form of a police telephone box to better blend in with modern society. But, what are the limits of a TARDIS' forms? How often can it change? Could a Time Lord appear in, say, the telephone box form, change its form to a smaller pocket-size version and carry it around and have it shift back when needed?
gpt
IIRC, *ideally*, it arrives somewhere, scans the environment to determine what would be least conspicuous, then transforms into whatever that is.  What the Doctor's Tardis does is arrive, scan the environment, determine what would be least conspicuous, and then just turns into a police box anyway.