What is considered a "Form" for the Pokedex research task?

Question

One of the research tasks that seems to be present on most Pokémon's research task is "Number of different forms you've obtained." My initial assumption is this referred to catching the regional variants of Pokemon, but apparently I've already managed to complete this entry for some Pokemon, despite having only caught a few pokemon in the first area. I've noticed that I have two different genders for these Pokemon, so I'm assuming that a Pokemons gender must qualify as one of its "forms". Although now I'm confused what exactly is considered a form, and so I'm looking for some clarification.

What is considered a "Form" for the "Number of different forms you've obtained" research task?

Answer 1

According to various guides (here and here), "form" refers to the following:

• Obtaining both male and female of the species if gender causes them to look different (for example, Sneazel and Bidoof)
• Obtaining regional variants of the species. For example, both Johtoian and Hisuian Sneazel can be caught in Legends Arecus, so you'd need to catch both genders for each region
• Obtaining each variant that would change the species type (for example, Rotom and Wormadam)
• Obtaining each variant that would change the species look (for example, the genies Incarnate/Therian forms and Burmy)

Shiny form seems to be excluded, given the fact that you've already completed this entry for various species