I assume you know the basic calculation of the h index?
https://en.wikipedia.org/wiki/H-index#Calculation
The difference between different databases is just the dataset they use, so Web of Science has a rather restrictive selection of journals which they consider, Scopus has a few more, Researchgate also takes in manual uploads without verification that it's a legitimate journal and Google Scholar basically considers everything that's somehow on the internet and hasn't explicitely been flagged "fraudulent".
"Dataset" doesn't only include the papers you published, but also those that cite you. Therefore, since Scopus has 40.000 journals in it and Web of Science only 22000, it is expectable that your Scopus H index will be higher since evaluating 18000 additional journals naturally results in a higher citation count.
Dear Dunia S. This is because the h-index in Scopus is wrong: it should be h=2 (since you have two papers with at least two citations and not h=3 because then you need three papers with at least three citations). Best regards.
PS. I noticed that your 2023 paper is not present in your RG profile.
Article Metaheuristic methods to identify parameters and orders of f...
you can just claim authorship and it will be added to your profile.