A PhD is a challenging endeavour.
You will discover that there are a thousand things to know and skills you'll need to master.
For example you have to know a good tool of data processing. During your experiments you have at some point to analyze data and make a graphic representation of it. If R programming (or Python) is too much for you, then you have to know at least Excel.
Have a good knowledge of Excel is must for most of new PhD students.
This would imply that you know good statistics at least descriptive statistics. Here is a good course on that Introduction to Statistics: Descriptive Statistics (https://www.edx.org/course/introduction-statistics-descriptive-uc-berkeleyx-stat2-1x?source=aw&awc=6798_1492529387_388681aa89ae0ca0bd141c36f9fae7b4&utm_source=aw&utm_medium=affiliate_partner&utm_content=text-link&utm_term=85386_VigLink%20Content)
As a PhD you need to write your results and publish your results. A good tool online for that purpose is Overleaf. Overleaf: Real-time Collaborative Writing and Publishing Tools with Integrated PDF Preview (https://www.overleaf.com/) . To use it you have to know Latex markup language so this is also something you want to learn.
Presenting your results by using a power point presentation is also a skill that every PhD student must have. Not always this part is easy, specially if you don't master good fluent English or if you are an introvert and don't like that much to talk in front of other researchers.
A good online tool for that is Presentation Software | Online Presentation Tools | Prezi (https://prezi.com/)
This post originates from my Quora answer you can find here https://www.quora.com/What-are-some-tools-and-website-that-every-new-PhD-student-should-know