Add instruction how to upload files

docs/api/sending_files.md

@@ -0,0 +1,67 @@
+# How to upload file?
+
+As says [official Telegram Bot API documentation](https://core.telegram.org/bots/api#sending-files) there are three ways to send files (photos, stickers, audio, media, etc.):
+
+If the file is already stored somewhere on the Telegram servers or file is available by the URL, you don't need to reupload it.
+But if you need to upload new file just use subclasses of [InputFile](./types/input_file.md). Here is available two different types of input file:
+
+- `#!python3 FSInputFile` - [uploading from file system](#upload-from-file-system)
+- `#!python3 BufferedInputFile` - [uploading from buffer](#upload-from-buffer)
+
+!!! warning "Be respectful with Telegram"
+    Instances of `InputFile` is reusable. That's mean you can create instance of InputFile and sent this file multiple times but Telegram is not recommend to do that and when you upload file once just save their `file_id` and use it in next times.
+
+## Upload from file system
+By first step you will need to import InputFile wrapper:
+```python3
+from aiogram.types import FSInputFile
+```
+
+Then you can use it:
+```python3
+cat = FSInputFile("cat.png")
+agenda = FSInputFile("my-document.pdf", filename="agenda-2019-11-19.pdf")
+```
+
+### FSInputFile(...)
+
+|Argument|Type|Description|
+|---|---|---|
+| path | `#!python3 Union[str, Path]` | File path |
+| filename | `#!python3 Optional[str]` | Custom filename to be presented to Telegram |
+| chunk_size | `#!python3 int` | File chunks size (Default: `64 kb`) |
+
+## Upload from buffer
+
+Files can be also passed from buffer (For example you generate image using [Pillow](https://pillow.readthedocs.io/en/stable/) and the want's to sent it to the Telegram):
+
+Import wrapper:
+
+```python3
+from aiogram.types import BufferedInputFile
+```
+
+And then you can use it:
+```python3
+text_file = BufferedInputFile(b"Hello, world!", filename="file.txt")
+```
+
+### BufferedInputFile(...)
+|Argument|Type|Description|
+|---|---|---|
+| buffer | `#!python3 bytes` | File path |
+| filename | `#!python3 str` | Custom filename to be presented to Telegram (Required) |
+| chunk_size | `#!python3 int` | File chunks size (Default: `64 kb`) |
+
+Also you can read buffer from file:
+
+```python3
+file = BufferedInputFile.from_file("file.txt")
+```
+
+### BufferedInputFile.from_file(...)
+|Argument|Type|Description|
+|---|---|---|
+| path | `#!python3 Union[str, Path]` | File path |
+| filename | `#!python3 Optional[str]` | Custom filename to be presented to Telegram |
+| chunk_size | `#!python3 int` | File chunks size (Default: `64 kb`) |

docs/api/types/input_file.md

@@ -14,5 +14,5 @@ This object represents the contents of a file to be uploaded. Must be posted usi
 - `from aiogram.api.types.input_file import InputFile`
 
 ## Related pages:
-
 - [Official documentation](https://core.telegram.org/bots/api#inputfile)
+- [How to upload file?](../sending_files.md)

docs/api/types/input_media_animation.md

@@ -30,3 +30,4 @@ Represents an animation file (GIF or H.264/MPEG-4 AVC video without sound) to be
 
 - [Official documentation](https://core.telegram.org/bots/api#inputmediaanimation)
 - [aiogram.types.InputFile](../types/input_file.md)
+- [How to upload file?](../sending_files.md)

docs/api/types/input_media_audio.md

@@ -30,3 +30,4 @@ Represents an audio file to be treated as music to be sent.
 
 - [Official documentation](https://core.telegram.org/bots/api#inputmediaaudio)
 - [aiogram.types.InputFile](../types/input_file.md)
+- [How to upload file?](../sending_files.md)

docs/api/types/input_media_document.md

@@ -27,3 +27,4 @@ Represents a general file to be sent.
 
 - [Official documentation](https://core.telegram.org/bots/api#inputmediadocument)
 - [aiogram.types.InputFile](../types/input_file.md)
+- [How to upload file?](../sending_files.md)

docs/api/types/input_media_photo.md

@@ -26,3 +26,4 @@ Represents a photo to be sent.
 
 - [Official documentation](https://core.telegram.org/bots/api#inputmediaphoto)
 - [aiogram.types.InputFile](../types/input_file.md)
+- [How to upload file?](../sending_files.md)

docs/api/types/input_media_video.md

@@ -31,3 +31,4 @@ Represents a video to be sent.
 
 - [Official documentation](https://core.telegram.org/bots/api#inputmediavideo)
 - [aiogram.types.InputFile](../types/input_file.md)
+- [How to upload file?](../sending_files.md)