bros
There are many iptv app. personally i prefer this few iptv extreme , ott navigator and for those that have only m3u playlist, you may consider televizo or ott player
which only support m3u playlist.

For link you maybe subscribing to a paid service and a link usually with userid and password will be issued to you when u subscribe. As for free playlist
there are those on the net which you can try your luck to search for them.
You can also built your own playlist if you have technical knowledge(not to difficult) eg. I have a built m3u playlist for Singapore Free to air channels( i.e chn 5, 8, u ,suria ,Versa.. and CNA) which mean i can have my TV any where and any time, for any important news.
Is it creditable and safe?
If you subscribe to paid service some providers you may face MIA (not safe with your money)
Creditable provider like starhub and Singtel is most reliable but watch for the price.
Other playlist from the net depend on your luck ( some is good but most fail)
Any thoughts on those Software or links?
If you are referring to copyright downloading of copyright protected material is illegal, however you are in the grey area if you are just watching.
There are many of those china app that come with many channels are usually temporary it work for a while then it will end it life. if you dont mind installing
and uninstalled. However, there is one important thing to note is that these software maybe the gateway from your phone to some user for whatever reason
So remember not to install any of those to a device that come with important app like banking or trading app and etc.
if you installed into a tv box or a table just for entertainment, i think that not too bad

goodluck dont beleive all i say seek professional advice when nec.