The Amstrad CPC range supported 3 basic screen modes:
mode 0 - 160x200, or 20x25 characters, with a palette of 16 colours
mode 1 - 320x200, or 40x25 characters, with a palette of 4 colours
mode 2 - 640x200, or 80x25 characters, with a palette of 2 colours
Any of these colours could be selected from a total palette of 27 colours, which is based on 3 settings (off, half intensity, full intensity) for red, green and blue.
Of course, it provided a complete standard 7-bit, 128 character ASCII character set, as part of its 256 total character set which, by default, provided a range of graphics symbols including some fractions, 16 Greek characters mostly used in maths, other useful symbols as well as a typical range of boxes, bars and blocks for creating graphical elements.
The entire 256 symbol character set is re-definable, even from BASIC, with simple commands, so it has the ability to produce, as text, any symbol that can be created in an 8x8 grid.
The firmware provided ability to place these characters anywhere on screen, and of course the built in BASIC interpreter allowed full, standard control over these - the usual LOCATE x,y, PRINT, etc.
Where this differs from many systems of the era, and what CPC Wiki is referring to, is that there is no seperate "text" mode. All modes can mix text and graphics at will. Nor is the text output limited to a fixed grid - you can actually locate the cursor to any pixel and trigger a standard firmware text output, even from BASIC.
What it does lack is support for hardware sprites - basically larger multicolour characters that can be moved on-screen. Programmers had to implement these in machine code.
The result was that generally, games used mode 0 to access the maximum colour palette, while business programs used mode 2 for the 80x25 text that was standard at the time. The machine would actually run CP/M and emulate a Zenith/Heath terminal which meant a huge range of industry standard software of the era could be run, such as dBASE II, Wordstar, MS BASIC, Turbo Pascal, etc.
(p.s. some comments suggest the colour monitor was not suitable for the 80x25 text mode. I owned one for many years and can vouch that it was perfectly decent and useable for its time. Was it the best? No... but there were also a lot of worse looking displays back in the 80s!)