Lure modules are one of the multi-purpose items used to modify a Pokestop.
When used, it creates a swirl of flowers or various other patterns which can be identified by any trainer from accessing the in-game map.
Lure modules also act as a key feature that increases the spawn rate around an 80m radius of the Pokestop.
It can also be used to evolve multiple Pokemons depending on the typings.
How To Get Lure Modules in Pokemon Go

Lure modules can be obtained from the in-game shop by spending Pokecoins.
A free-to-play experience can be obtained after completing certain time-limited events, special research tasks and timed research.
One can get it as a reward for levelling up their character.
How To Install Lure Module in a Pokestop

To install a lure module on Pokestop, click on the pink-coloured bar below the name of the Pokestop.
Upon installation, your name will be visible on the Pokestop until the effect of the module ends.
Types of Lure Modules and Pokemon Evolving Under Its Effect

The current version of the game consists of 5 kinds of lure modules- regular, magnetic, glacial, mossy, and rainy.
It is expected that the developer will release some more modules in the upcoming patches.
Magnetic Lure Modules

An electronic magnetic module attracts Pokemon with an electrical field around them.
The following species evolve when it's nearby the modules.
Magneton, an electric/steel Pokemon from gen 1 evolves from magnemite using 25 magnemite candies.
Magneton evolves into magnezone using 100 magnemite candies under the influence of magnetic lure module.
Note: Shadow magnezone is one of the strongest electric-type meta raid attackers, i.e. it deals more damage per second in its shadow version and is highly used in PvE.
Nosepass, the rock/steel Pokemon from gen 3 is one of the bulkiest contenders in the Go Battle League (PVP), it evolves into probopass after using 50 nosepass candies when nearby a magnetic module.
Charjabug, the newly released electric/bug Pokemon from gen 7 evolves from grubbin into Charjabug using 50 grubbin candies, further into Vikavolt with the use of 100 grubbin candies when nearby a magnetic lure.
Glacial Lure Modules

A frosty lure module that attracts cold and ice-loving Pokemons.
Eevee, a normal type Pokemon from gen 1 is one of the cutest and fan favourites with its 8 evolution stages one being glaceon, an ice type from gen 4.
Glaceon evolves from Eevee with the use of 25 Eevee candies in the range of a glacial lure module.
Rainy Lure Modules

This module was released in May 2021, a wet module that attracts Pokemon that loves rain.
Another fan-favourite pseudo-legendary Pokemon from gen 6 made its appearance in the XYZ series as one of the strongest Pokemon in Ash's roster.
For the first time it was released in Pokemon go in May 2021.
Sliggoo evolves from goomy after using 25 goomy candies, further it evolves into goodra with the use of 100 goomy candies when in the range of the rainy module.
Mossy Lure Modules

A natural lure module that attracts grassy and Marsh-loving Pokemon.
Eevee can evolve into leafeon with the use of 25 Eevee candies when nearby a mossy lure module.
Note: Shadow Pokemons take more candies to evolve and are more expensive to level up but do a significant amount of damage.
