Hi @MartinVargas
You can try the following to enable the Tooltip for your field that will suffice your need. Below are the steps for you.
1. Go to https://make.powerapps.com/ - choose your environment
2. Under Data > Tables > choose the table
3. Select "Forms" Tab > Choose your main form > Edit in new Tab
4. You can see an option called "Switch to classic"
5. Double click the field where you need tooltip/help text
6. Under "Details" Tab > Click Edit > under "Description" > add your tooltip/help text

7. Hit Save and close and click ok
8. Remember to publish your form in classic mode.
Once published > Click publish again in the design mode and close the form design
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In Portal studio
1. Pres sync configuration and browse the website. And press "Ctrl+F5"
Output:

If you need customisation like what you described then it requires bit of customisation using jquery and CSS
Hope it helps.
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