IPTV is a delivery method, not a legal category by itself. Whether particular content is authorized depends on licensing and location. Before buying, ask the provider about rights for the channels you want to watch.
What to check before you start
Protect your account details and install player apps from trusted sources. Keep your device software current. If your device requires changes to security settings, understand the consequences first.
Practical next step
Content availability and legal rules differ by location. Seek qualified local advice for a specific legal question.