Continuing on from the article Robb Knight posted. Here are the apps I use in each category. 

• Mail client: HEY web app
• Mail Server: HEY custom domains
• Notes: Notes.app, Bear
• To-Do: Things 3
• iPhone Photo Shooting: iOS Camera
• Photo Management: Photos.app
• Calendar: Apple Calendar
• Cloud file storage: iCloud Drive
• RSS: n/a
• Contacts: Contacts.app
• Browser: Safari
• Chat: iMessage
• Bookmarks: Safari (unused)
• Read It Later: n/a
• Word Processing: Google Docs, Ulysses
• Spreadsheets: Google Sheets
• Presentations: Keynote
• Shopping Lists: Bear
• Meal Planning: n/a
• Budgeting & Personal Finance: YNAB
• News: Mastodon, Reddit, Reuters
• Music: Apple Music
• Podcasts: Overcast
• Password Management: 1Password