Export, import, back up and print in Task List by Zaweba
Back up everything as JSON, export tasks to CSV, print or save a list as an A4 PDF, and rely on 14 daily copies in Task List by Zaweba.

Everything in Task List by Zaweba lives in one file on your PC, and the File menu gives you four ways to get it out or put it back. Export a full backup saves everything as JSON. Import restores from such a backup. Export tasks as CSV writes a spreadsheet-friendly file. Print or save the list as PDF produces an A4 page. Behind those, the app also copies its database automatically every day and keeps the newest 14 copies.
Each has its own job, and knowing which to reach for saves trouble.
A full backup
File, then Export a full backup, writes everything in the app to a JSON file. One thing is left out on purpose, the email password, so a backup can be stored or carried without exposing your mail account.
Use it before a big change, such as clearing completed tasks, before moving to a new PC, or on a regular rhythm if you like your own copies alongside the automatic ones. Put the file somewhere other than the PC itself, such as a USB stick or a backup drive.
Importing
File, then Import, reads a full backup back in. It replaces everything currently in Task List, so it asks first. Before replacing anything it takes a safety copy of what is there, which means a mistaken import can be undone by importing that copy.
Moving to a new computer is the usual case. Export on the old PC, install Task List on the new one, import, then enter the email password again in Settings, since it was never in the backup.
CSV for spreadsheets
Export tasks as CSV writes your tasks to a UTF-8 CSV file, which Excel and other spreadsheets open. It is formula-safe, meaning a task title that happens to start with a symbol a spreadsheet would treat as a formula is written so that it stays plain text. That protects you from odd results, and from the risk of a spreadsheet running something unexpected.
CSV suits reporting, timesheets, sharing a list with someone who uses a spreadsheet, or keeping a record before you clear completed tasks.
Printing and PDF
Print or save the list as PDF produces an A4 page of the list. Print it for a fridge door, a meeting or a shopping trip. Save it as a PDF to email a list to someone, or to keep a dated snapshot of where a project stood.
A printed list is a good companion to the app on days away from the PC: tick it with a pen, then tick the same tasks in Task List when you are back.
The daily copies
You do not have to remember any of this for basic safety. Task List copies its database every day into a backups folder beside the main file in your user data folder, keeping the newest 14. If something goes wrong, there are two weeks of copies to fall back on.
Choosing the right one
For moving or restoring, use a full backup. For a spreadsheet, use CSV. For paper or a document to send, use print or PDF. For peace of mind day to day, the automatic copies are already running. One caution: CSV is a one-way export for reading elsewhere, not a way to move tasks between PCs. For that, always use a full backup and Import.