Yes, the iGaming industry is legal in many countries. The main thing is to register the company correctly and obtain the appropriate permit (a gambling license). Terms of legalisation may vary depending on the selected offshore zone.
It is better to place the information about the number and validity term of your license in a special section on the bottom panel of the website. Thus, anyone will be able to verify the legitimacy of your project and clarify what jurisdiction has issued the permit.