Here is a list of the default hotkeys when playing Minecraft: Java Edition:

1. Scroll - Scrolls through your quick bar and the chat when opened. 
2. Esc - Opens the game menu and allows cursor control. It also pauses single-player games. 
3. F1 - Toggles HUD 
4. F2 - Takes screenshots and stores them in your .minecraft folder 
5. Shift + Left Mouse Button  
   Interactions: 
   • • Clicking an item or stack will move it between inventory and stack. 
     • When a container is open, shift + clicking on an item will move up to a stack between the container and the inventory. 
     • When a furnace is open, shift + clicking an item or stack in the furnace moves it to the applicable inventory slot. 
     • When crafting, shift + clicking on the crafted item automatically crafts the maximum number of the selected item for the materials be used (up to one stack), and it will move all the crafted items to the inventory. 
     • In the survival inventory tab of the creative inventory, shift + clicking the ‘X’ clears the whole inventory in any other tab, shift + clicking an item puts a stack into the hotbar. 
6. F3 - Toggles the debug menu 
   When the debug menu is open: 
   • • 1-9 Number Keys – Displays a more detailed view of the graph on the right 
     • 0 Key - Display less detailed graph 
     • Shift + F3 - Display profiler graph 
     • F3 + Q - Displays help menu that lists all debug menu shortcuts 
     • F3 + A - Reloads all chunks 
     • F3 + T - Reloads all textures, sounds and web-loaded client resources. This is useful for texture pack creators. 
     • F3 + P - Toggle the auto-pause when the window is out of focus 
     • F3 + H - Toggle detailed item descriptions 
     • F3 + C - Hold this key for 10 seconds to trigger a manual debug crash, after the keys are released. 
     • F3 + B - Toggle Showing hitbox around entities 
     • F3 + D - Clear chat history, including previous commands 
     • F3 + N - Cycles between spectator mode and the previous game mode.
     • F3 + G - Show the chunk boundaries immediately surrounding the player. 
7. Movement Hotkeys: 
   • • Space - Jump 
     • Double Tapping Space - Toggle fly mode in creative mode 
     • Left Shift - Sneak 
     • Left Control - Sprint 
     • A - Strafe Left 
     • D - Strafe Right 
     • S - Walk Backward 
     • W - Walk Forward 
8. Left Mouse - Attack/Mine 
9. Middle Mouse (Scroll wheel button) - Pick Block 
10. Right Mouse - Use Item/Place Block 
11. Q - Drop item 
12. Ctrl + Q - Drop whole stack of items. (For Macintosh users, use Control + Command + Q- Otherwise it will close your game) 
13. 1-9 Number keys - Select hotbar slot of the number you pressed 
14. E - Open Inventory 
15. F - Swap held item(s) to offhand 
16. Creative Mode: 
    • • X + 1-9 Number Key - Loads Toolbar Activator 
      • C + 1-9 Number Key - Saves Toolbar Activator  
17. Multiplayer: 
    • • Tab - See the List of Players 
      • While in chat window + tab - Cycle through possible commands or arguments and also auto-completes player names 
      • T - Open Chat 
      • / - Open Command (Open the chat window with “/” character already entered) 
      • Shift + Up Arrow/Down Arrow- In the multiplayer server selection menu, shift + up and shift + down moves a server name to a specific position. You can also hold shift while a server name is selected and left click another server name, they will swap positions in the menu. 
18. L - Advancements 
19. F5 - Toggle perspectives (between third person and rear-view) 
20. F11 - Toggle fullscreen