Confusion about the linking method of dynamic libraries like d3d11

As far as I know, we need __declspec(dllexport) to export symbols to import libraries (.lib files), which are required by implicit linking.
When I glanced at d3d11.h, I found that all functions don't have __declspec.

But how to explain the existing import library d3d11.lib? Could implicit linking works without __declspec(dllimport) in headers when we try to call functions in them.

Could implicit linking works without __declspec(dllimport) in headers when we try to call functions in them?

This applies to Win .dlls (when working with VStudio).

There are 2 stages:

1. Create the .dll (which will export symbols)

There are multiple ways (3) to export symbols from a .dll. Check:

1. [MS.Learn]: Exporting from a DLL Using __declspec(dllexport)

2. [MS.Learn]: Exporting from a DLL Using DEF Files

3. [MS.Learn]: /EXPORT (Exports a Function)

Might also want to read:

• [SO]: How to build a DLL version of libjpeg 9b? (@CristiFati's answer) (especially Export data from the .dll section)

• [MS.Learn]: Exporting from a DLL

2. Use (symbols from) the .dll

This is typically when building a client for the (above) .dll (could be an app or another .dll).

According to [MS.Learn]: Import into an application using __declspec(dllimport) (emphasis is mine):

Using __declspec(dllimport) is optional on function declarations, but the compiler produces more efficient code if you use this keyword.