Setup of Tabs vs Whitespaces on most common IDEs

If for you it is important to correctly format your code, you know very well about the whitespaces versus tabs dilemma.
Generally, in the past tabs were preferred, because they optimized source code file sizes; they also allowed to switch between 2 and 4 spaces easily.
In the last times, I see more and more spaces used instead, as they offer a more consistent view across different IDE configurations.
Even if personally I still prefer tabs (and luckily I am not alone), in this guide I will explain how to configure them in the most popular IDEs.
EditorConfig
The EditorConfig settings override the local developer settings, so I strongly suggest using this approach to have a consistent and reproducible working environment across all developers of a team.
Sadly not all settings are available here, so in the other cases you'll still need to fall back to the specific IDE settings that will follow later.
- How to choose between spaces and tabs
indent_style = {space|tab}
indent_size = {4|tab}
tab_width = 4 - How to visually display whitespaces
n.a. - How to reformat existing code
n.a. - Other useful settings
- How display line numbers
n.a. - How display indentation lines
n.a.
- How display line numbers
Visual Studio for Windows
- How to choose between spaces and tabs
From Tools | Options | Text Editor | All Languages | Tabs, here choose "Insert spaces" or "Keep tabs"
From this same dialog, you can also configure "Tab size" and Indent size" - How to visually display whitespaces
You need to open a source code file before finding the following setting
From Edit | Advanced | "View White Space" (Ctrl+E, S) - How to reformat existing code
From Edit | Advanced | "Format Document" (Ctrl+E, D) or "Format Selection" (Ctrl+E, F) - Other useful settings
- How display line numbers
From Tools | Options | Text Editor | All Languages | General, "Line numbers" - How display indentation lines
From Tools | Options | Text Editor | General, "Show structure guide lines"
- How display line numbers
Visual Studio for Mac
- How to choose between spaces and tabs
From Visual Studio | Preferences | Source Code | Code Formatting | Text File | Whitespace, "Convert tabs to spaces"
From this same dialog, you can also configure "Tab width" and Indent width" - How to visually display whitespaces
From Visual Studio | Preferences | Text Editor | Markers and Rules | Show invisible characters, here choose "Always", "Selection" or "Never" - How to reformat existing code
From Visual Studio | Edit | Format, "Format Document" (Ctrl+I) - Other useful settings
- How display line numbers
From Visual Studio | Preferences | Text Editor | Markers and Rules, "Show line numbers" - How display indentation lines
From Visual Studio | Preferences | Text Editor | Markers and Rules, "Show indentation lines"
- How display line numbers
Visual Studio Code
- How to choose between spaces and tabs
From File | Preferences | Settings | Text Editor, "Detect Indentation"
From File | Preferences | Settings | Text Editor, "Insert Spaces"
From File | Preferences | Settings | Text Editor, "Tab Size" - How to visually display whitespaces
From File | Preferences | Settings | Text Editor, "Render Whitespace" - How to reformat existing code
From View | Command Palette (Ctrl+Shift+P), "Format Document" (Shift+Alt+F) - Other useful settings
- How display line numbers
From File | Preferences | Settings | Text Editor, "Line Numbers" - How display indentation lines
From File | Preferences | Settings | Text Editor, "Render Indent Guides"
- How display line numbers
Xcode
- How to choose between spaces and tabs
From Xcode | Preferences | Text Editing | Indentation | "Prefer Indent Using", here choose between "Spaces" or "Tabs"
From this same dialog, you can also configure "Tab Width" and "Indent Width" - How to visually display whitespaces
From Editor, Invisibles - How to reformat existing code
From Editor | Structure, "Re-Indent" (Ctrl+I) - Other useful settings
- How display line numbers
From Xcode | Preferences | Text Editing | Display, "Line Numbers" - How display indentation lines
There is no a permanent setting for this, but hovering over a structure and pressing Command will display the indentation guide
- How display line numbers
Android Studio
- How to choose between spaces and tabs
From File | Settings... | Editor | Code Style | Kotlin | check or remove "Use tab character"
From the same dialog, you can also configure "Tab size" and "Indent" - How to visually display whitespaces
You need to open a source code file before finding the following setting
From View | Active Editor | Show Whitespaces - How to reformat existing code
From Code | Reformat Code (Ctrl+Alt+L) - Other useful settings
- How display line numbers
You need to open a source code file before finding the following setting
From View | Active Editor | Show Line Numbers - How display indentation lines
You need to open a source code file before finding the following setting
From View | Active Editor | Show Indent Guides
- How display line numbers