1. HackerRank

If you are a beginner and want to develop a basic concept then I will suggest you go with HackerRank because they have some good problems for beginners which is sorted level wise i.e. you will get problems in increasing difficulty level. And by applying some basic logic you will able to crack them.

2. LeetCode

LeetCode has straight to the point problem statements. Once your solution has been approved, it lists it against all approved solutions in the same programming language and the percentage of how many solutions you beat out for speed.
There are 3 main difficulty levels are Easy/Medium/Hard.

Aside from the coding problems itself, the LeetCode community is its most valuable asset. It’s the #1 thing users talk about, and it’s a great resource for getting insight into how others are solving problems and learning from others’ mistakes.

3.CodeWars

Codewars has a captivating interface with unique ways of presenting the challenges, naming them as Katas, where coders gain skills and challenge other coders in Kumite. It’s one of the best places to learn to code and to have fun at the same time. Master your current language of choice, or expand your understanding of a new one. The challenges provide discussion boards as well as the ability to view user solutions.

4.HackerEarth

HackerEarth features over 8000 questions, 2000 challenges, and 1000 hackathons. This platform has a thriving community of 3 million developers. There is also a remote interview feature plus analytics for companies to see your statistics.

5.CoderBryte

Coderbyte is an online collection of algorithms and full-stack coding challenges and interview kits, which can be solved in 15+ languages including React, Python, and SQL directly in their online editor. The challenges come with official solutions and tens of thousands of user solutions and discussions. There are also tutorials on topics like advanced JavaScript features, data structures, and algorithm interview questions.

I hope you will found these websites helpful.