You remember drawing the plan. You remember the notebook too, but there are four similar ones on the shelf, and the drawing could be in any of them. Searching your computer for the project name will not help unless you have given it something to find.
A digital archive can start with a plain list of notebook references. You do not have to scan every page or convert your handwriting into editable text. The useful result is simpler: type a subject, find the right reference and open the page you need.
Give every notebook an address
Write a short identifier inside each notebook and on its label. A sequence such as N01, N02 and N03 is enough. If your notebooks already have names that distinguish them clearly, use those instead.
Number the pages that contain material you want to reference. You can number the whole notebook as you go, but keep the method consistent. A reference such as "N04, page 36" needs to point to the same page every time.
Create one digital note or document called "Notebook index". For each useful entry, record a descriptive title, the notebook identifier and the page number. Add a few words you might search for later.
For example: "Kitchen shelf measurements; N04, page 36; alcove, brackets, depth." These are sample labels, but the principle matters: the vocabulary should match how you would look for the information. You will probably search for "shelf", not "Thursday thoughts".
Decide which pages need a digital copy
Scan a page when you want to refer to it away from the physical notebook, share it, or keep another copy of something important. A page of crossed-out options may need only an index entry. An annotated drawing that a colleague needs tomorrow probably needs an image.
You can also type a short summary instead of scanning. Include the source reference so you can check the original. If the summary contains a decision, distinguish it from ideas that you were still considering on the page.
For workplace or client material, follow the rules that apply to those records before uploading them to a scanning service or personal storage account. Cropping a photograph can remove an unrelated note at the edge, but it does not make every document suitable for sharing.
Capture a page without forcing the notebook flat
Work on a clean surface with enough light to read the whole page. Support the notebook at the angle it opens comfortably. Avoid pressing hard on the binding simply to obtain a flatter image.
Hold the camera as square to the page as practical, keep your shadow clear and check the corners. If writing disappears into the gutter, take a second photograph from a better angle. Two readable images are more useful than one tidy image with missing words.
Before closing the notebook, open the captured file at a readable size. Check the smallest writing and any pale pencil marks. Look especially closely at measurements, dates and names. A blurred number can turn a reference into a new problem.
Name the file while the page is still in front of you. "N04-p036-kitchen-shelf" connects the image to the physical source without relying on an automatic camera filename. Put the file reference into your index.
Treat handwriting recognition as an extra
Some software can search or recognise handwriting, but results depend on the tool and the page. Test it with your own writing before making it the only way to find notes. A recognisable heading and a few typed keywords give you a fallback.
If you convert a page to text, compare the result with the image before using exact information. A correct-looking sentence can still contain the wrong amount or a missing word. Keep the image as the reference when the wording matters.
Avoid editing the only copy of the scan while tidying it. Keep an original image and make any marked-up or cropped version separately when you need to preserve the full page.
Test the archive with a real search
After adding a few entries, close the notebooks and try to find something by subject. Can you reach the page without remembering the date you wrote it? Does the reference lead to a readable image or an identifiable notebook on the shelf?
Fix the weak point you encounter. You may need a clearer title, another keyword or a better label on the notebook. There is little benefit in scanning a hundred more pages before solving that first problem.
Keep another copy of the digital material somewhere appropriate, and occasionally check that it opens. For irreplaceable notes, retain the physical notebook too. A workable archive lets you return to paper with a clear answer to a small question: where will this page be when you need it again?