If you only want to make keyword research, use this tool here:
https://tryastro.app/
its $9 per month. but i think its only available for MacOS.
Usually I would check the popularity and also the difficulty. high popularity & low difficulty = best keyword
then, its important to understand ASO when it comes to keywords:
Title > subtitle > keywords. And within them, the order matters. Your absolute main keyword should be on first place of the title. If you have a brand, put your brand name last. Example: Your app brand name is: BHW. Your main keyword is "Digital Marketing". You have 30 letters available. Your title should be: "Digital Marketing & SEO - BHW". You would put your main keyword first, a secondary keyword (second most important!) and then your brand name. Just need to make sure you use almost ALL the available letters.
Some more rules regarding keywords:
- Do not repeat keywords (it should never be twice)
- Do not split
- Do not use stop words
- Separate with commas (digital,marketing,seo,online,learn,ad........) etc.
- Do not use plurals (means: use "ad" instead of "ads" or "image" instead of "images")
- Do not include your company name or category
- Order matters (most important first)
- Beware of special characters (ö,ü,ß, ', etc.)