Some applications will use JSON to store data. This data is usually not meant to be used by end users.
When to Use JSON
Most text editors can open JSON files and let you read and edit them. There are not many data analysis apps that let you import JSON. You can analyze JSON data by uploading your file to your datasets.
When to Use TSV
TSV files are useful for storing tabular data. Some data analysis apps like excel can use them as inputs without too much hassle. One tsv row becomes one row in excel.
TSV files can also be easier to read in text editors than json files. Sometimes they might convert tabs to spaces though. so if you save changes your tsv file might not work with other applications.
If you want to convert your data to tsv then you can use one of the other converters.
How to Convert TSV to JSON online
Upload your tsv file using the input at the top of the page
Your tsv data will be converted and a json file will start downloading automatically.