Circa automatically parses several types of text files
Here is a video Circa tutorial that walks through the types of files you can plot in Circa, as well as how to export a file from Excel.
There are only a few requirements for files you can plot with Circa:
Rows and columns
Each file must be neatly formatted into rows and columns, where columns are separated by tabs, spaces, or commas. The delimiter is detected automatically.
Each file must have a header in the first row, which gives the name for each column.
Chromosome and position
There must be some column you can choose as a chromosome name and another column that gives the position within that chromosome. For instance, a BED file has the chromosome name in the first column and the start location of the feature in the second column: chr1,2989483.
The files must be smaller than 10MB. Anything bigger than that would create a really crowded plot anyway, so it is best to filter your data or consolidate it if the file is too big. This will also better show the information you are trying to convey
Circa cannot read binary files or any or formats that are not human-readable in a text editor like nano, vim, or TextEdit. Excel files can be exported to CSV by going to File -> Save As… and changing the File Format in the dropdown to CSV.
Check out the other tutorials for Circa on the Circa tutorials page.