All ESRI map viewer are for public user to use,
no need to sign in arcgis online.
The only difference is after you sign in your arcgis online account, you can save your edited map to your organization's account.
Without sign in to any organization, the save button is disabled grey out, you can't save your map to anywhere.
1. ESRI's map viewer
Build with 4th generation Arcgis javascript api V4.x
https://www.arcgis.com/apps/mapviewer/index.html
has some bugs has not been fixed by ESRI, but you should use this one
1. 1 How to use ESRI's map viewer
https://transparentgov.net/cleargov1/1741/how-to-use-esris-map-viewer
2. ESRI's ( classic ) map viewer
Build with 3rd generation Arcgis javascript api V3.x
https://www.arcgis.com/home/webmap/viewer.html
2. 1 How to use classic map viewer
https://transparentgov.net/cleargov1/1742/how-to-use-classic-map-viewer
3. ESRI web app viewer
Build with 3rd generation Arcgis javascript api V3.x
www.arcgis.com/apps/webappviewer
Warning: here only refer to build-in version of Web appbuilder, not the developer edtion with custom widget. Developer edition must runs on your own web server( IIS or apache )
3. 1 You need copy and paste your app id here, https://www.arcgis.com/apps/webappviewer/index.html?id=xxxxx
4. ESRI Experience viewer
Build with 4th generation Arcgis javascript api V4.x
https://experience.arcgis.com/experience/your-apps-id-must-be-here
Warning: here only refer to build-in version of Experience Builder, not the developer edtion with custom widget.Developer edition must runs on your own web server( IIS or apache )
You must know your experience app ID, then append to this URL at the end
https://experience.arcgis.com/experience/. + your experience app ID
https://experience.arcgis.com/experience/3769e0a668b24857a6273f2203b8878f
A list of build-in version of experience builder sample
https://doc.arcgis.com/en/experience-builder/gallery/?categories=%2Fcategories%2Findustry%2Fgovernment%3A%20state%20and%20regional
Where to find ESRI map ?
Option 1:
google search ' your city name arcgis rest service '
Option 2:
Joseph Elfelt collect 3000+ arcgis rest service api endpoint over last 10+ years, you can download his list for free in PDF here
https://mappingsupport.com/p/surf_gis/list-federal-state-county-city-GIS-servers.pdf
His website is here https://mappingsupport.com/