Helo a chroeso.
Well, first of all let me kindly allert you that the main language here is English or the Welsh writing should be translated into English also in order for complete beginners to the language would feel welcome and not left out also. Short things in Cymraeg like this post is and some common expressions like “Diolch”, “Croeso” etc are permited.
Further on: The best area for practicing writing on this forum is the topic Be' 'dach chi'n gwneud rwan? A phethau arall yn Gymraeg - A topic to practice Welsh, open to all! where writings in only Cymraeg are allowed and welcome without translations.
The best area for practicing speaking is in our Slack community though about which you can find all the information in the topic Finding practice partners - a new resource - please share.
On this forum there also are quite some topics about finding parthers through the Skype (if you don’t use or don’t want to use Slack) although the Slack is the best idea at the moment.
To find the native Welsh speaker to practice with also the good resource is "Adopt a Learner" program over on useyourwelsh.com provided by @Nicky.
OH, and while I was in the process of replying and searching for the topics, @siaronjames did the work also, probably better than me.
Good luck in finding your best way to practice though.