Color Palette Generator: Adobe Color or https://color.adobe.com/
Hex Codes: can be used in Canva, Canvas, Google Slides/Docs, and more.
Can pick color from an image, color wheel, browse, or create your own
Can use this Hexcode as backgrounds for DIVs or Tables
Can use sliders to shift value or desaturate the color
(Background, Paragraphs, Text Boxes)
This is more advanced but if you have some comfort with HTML it is a nice tutorial.
She goes into using Coolors (similar to Adobe) to generate your color palette.