Create worksheet

Beverley2185 

I started tinkering with this problem before you had responded to Sergei. With that in mind, see what I had worked up below and in the attached workbook. Note: The workbook requires Excel 365 or Excel for the web. This is part of what I expect you to see:

We need more information from you to give the best ideas and solutions:

1. Which spreadsheet are you using? Excel 365 for Windows? Excel 365 for Mac? Excel for the web? An older version of Excel?
2. Please list the types of data that might be captured for each visit. E.g., start date-time, duration, owner, dog name, breed, birthdate (approximate; so spreadsheets can calculate age), vaccinations, notes on condition, behavior, types of grooming work to be performed (wash, cut…), fee, owner address, phone, email…
3. Do you need this workbook to help you in scheduling? (An Excel form might be used to capture information and verify available times.)
4. Will anyone else besides you use this workbook? (The reason for this question is that VBA code (e.g., macros) might be useful in some solutions. But if others can also edit the workbook, they could introduce malware.)

As Sergei indirectly indicated, you do not need a "worksheet for every day", but I would expect at least four worksheets (eventually): Clients (owner and dog Info), Visits (containing all scheduled grooming work, past and future), Daily, and Weekly, where the last two draw information from the Visits sheet.  Monthly and Annual sheets might be useful for summaries.  (Pivot tables are better at summarization, but you might not need that level of flexibility.)

Excel tables will be a good way of storing and referring to information. That's a more advanced technique than just storing data in ranges of cells, and navigating and maintaining a table is a little different, but it will likely be worthwhile. (E.g., pressing Tab while in the last cell of a table row navigates to the first cell of the next table row.) Using Excel tables allows you to write more meaningful formulas; e.g., a formula calculating the dog's age that starts with

=LET( when, MIN( [@Deceased], TODAY() ),

rather than

=LET( when, MIN( N3, TODAY() ),

SergeiBaklan, could you supply the correct syntax for a data validation formula that FILTERs from data in an Excel table row, plus a separate Excel table (tblVisits)?  My attempted formulas for column [Dog] (such as below) have not worked.  I want to filter to just the Dog names that apply to the [Owner Name] selected in the column just to its left.  (Another criterion to be added later.)

=FILTER( tblDogs[Dog], (tblDogs[Owner Name] = tblVisits@[Owner Name]) )