Every typeface used by Handwrite Studio is released under the SIL Open Font License, Version 1.1. That licence permits commercial use, redistribution and embedding the fonts in documents — which is exactly how this site uses them. The copyright notices below are reproduced as the licence requires.
Copyright 2014 The Caveat Project Authors (https://github.com/googlefonts/caveat) This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL
Full licence text: OFL.txt · Summary: this licence permits free commercial use, redistribution and embedding in documents.
Copyright 2018 The Fraunces Project Authors (https://github.com/undercasetype/Fraunces) This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL
Full licence text: OFL.txt · Summary: this licence permits free commercial use, redistribution and embedding in documents.
Copyright (c) 2011, Juan Pablo del Peral (juandelperal@htfonts.com), with Reserved Font Names "Gochi" and "Gochi Hand" This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL
Full licence text: OFL.txt · Summary: this licence permits free commercial use, redistribution and embedding in documents.
Copyright 2010 The Indie Flower Authors (kimberlygeswein.com), This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL
Full licence text: OFL.txt · Summary: this licence permits free commercial use, redistribution and embedding in documents.
Copyright (c) 2014, Indian Type Foundry (info@indiantypefoundry.com). This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL
Full licence text: OFL.txt · Summary: this licence permits free commercial use, redistribution and embedding in documents.
Copyright (c) 2010-2012 Patrick Wagesreiter (mail@patrickwagesreiter.at) This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL
Full licence text: OFL.txt · Summary: this licence permits free commercial use, redistribution and embedding in documents.
Copyright (c) 2010, Kimberly Geswein (kimberlygeswein.com) This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL
Full licence text: OFL.txt · Summary: this licence permits free commercial use, redistribution and embedding in documents.
The authoritative licence text accompanies each font in
/webfonts/licenses/ and at openfontlicense.org.
The UI typeface (Fraunces) is likewise OFL 1.1.