As a term itself describes it is a combination of two or more media. Media can be Audio, Video, Animations, Text or any other sort. You can combine all these Medias by using some softwares. These softwares are available in this website for free. We can categorize separate tools for editing videos, audio or text. Or we can simply use one single tool that can let us edit all these Medias in a single environment. All these Multimedia editors are available for free in this website.
Video Editors:
Magisto
Hyperlapse
Wondershare FilmoraGo
InShot
WeVideo
Splice
Adobe Premiere Clip
PicPlayPost
Blender
Lightworks
Shotcut
VSDC Free Video Editor
Machete Video Editor Lite
Avidemux
HitFilm
VideoShow
PowerDirector
Quik
KineMaster
VivaVideo

Audio Editors:

Adobe Audition
Ableton Live
Logic Pro X
GarageBand
Audacity
FL Studio
WavePad
Sound Forge
Studio One
Reason
Cubase
RX Post Production suite
Music Maker
ACID Pro
GoldWave
Power Sound Editor
Pydub
Easy spotify Music Converter
Ardour
AVS Audio Editor
Audio Tool
LMMS
Soundtrap
Audio Cleaning Lab
Leveator
Soundation
Auphonic
Acoustica
Any MP4 Audio Converter
AudioVAULT fleX
Diamond Cut DC8
HysteriaPlayer
Ocenaudio
SpectraLayers
Wavosour

Text Editing Tools:
Sublime Text
Atom
Notepad++
CoffeeCup-The HTML Editor
TextMate
Vim
UltraEdit
Coda
BBEdit
Visual Studio Code
Brackets
CodeShare