I use Day One, it's pretty good

Medium.com is good, or you could design your own blog? :D

I recommend following a specific methodology - in my case, the Bullet Journal system created by Ryder Carroll. This method inspired me to embrace pen-and-paper journaling. Writing by hand offers several benefits: it creates a stronger mental connection with your thoughts and provides a more peaceful, mindful experience compared to digital alternatives.

I would start simple with a text editor and expand when the habit starts to form. Many things fail because they are over-engineered right from the start, so I try to minimize this risk.